Had a lot of requests for this, and since the last one's been pushed off, and has had some changes, I figured I'd put a new one up.
This is the method we've been using nightly for about 2 months now. It works, and that's all I'm going to claim; we can back this up by the fact that we've had only 3 failed raids since the first time this method was successful. Considering the number that we've done overall, we're fast pushing a 20:1 win/loss ratio. So I'd say it's solid
So, let's cut to the chase.
Step One: Raid leadership
The following roles are needed before just about anything else:
Blaster/Melee Leaders: these guys keep the two main damage-dealing types on task and in line. Their job is to observe the trends of their specific ATs, funnel that info to the raid leader, and help to correct any issues that their AT is causing or experiencing (i.e. using cones and AoEs, etc.) These are not simple jobs, despite the description; while there's no blaster lead guide posted yet, take a look at
Ghost Tiger's melee lead guide to get a feel for the responsibility neccessary in the role.
Heal Team Lead: The healing team is the hardest working group in the raid. They keep the rest alive so that we can even stand a chance, and they can't do it without coordination. The heal team lead is the only lead that generally isn't on command team. Why? Simple. They're too damned busy to have time for dealing with the lead team chatter too. Doesn't mean they can't be on lead, but most, I've found, choose not to be to save themselves stress. Our medics are the best around, and they know what they're doing.
Genna's healer guide is about your best bet for understanding what your role is.
Illusion Drop Team Lead: A more streamlined role, but no less important. Your job is to consistently position the PA drop team in the best spot to not only get Hami aggro, but keep it off of the raid crew. You're also going to be responsible for hauling [censored] to wherever you need to when Hami decides to pick on the raid group, in order to get aggro BACK. You might spend 10 mins sitting and doing nothing but dropping PA, and then suddenly you're going to have to fly around like a bat out of hell trying to get your team moved so that the whole raid isn't wiped out by an angry cell. The Healing team sweats hard to keep the raid alive; the illusion team makes the workload managable in the first place. This leader is also often responsible for controller lead at the end(this depends on the raid leader; some prefer to do this directly). Regardless, all controllers should take a gander at
Lothiriel's guide on controlling Hami
Targetter: The targetter picks the target, and moves right up to it so that everyone can assist them and concentrate fire. Generally a hero with Fly, Phase Shift, and preferably a good video card. This is the raid point man, the guy that picks each target and guides the attention of everyone else. Considering the lag, it's not easy, because oftentimes you lose sight of targets, and you have to be able to switch to a new one very quickly and still make sure you're not leaving splits behind, before people get bored and blast whatever is nearby.
Bubbler: This is the anchor of the raid structure. While the targetter picks the targets, the bubbler uses their ability to be seen from a huge distance to gather everyone into a tight spot, so the heal blanket is at maximum effectiveness. The bubbler moves to a point directly below the target, so that melee and blasters alike can gather to hit it. It's not as easy as it sounds, either, because when the bubble moves, so does the raid. Gotta make absolutely certain you're going where you're supposed to, or the whole raid could get squashed by hami aggro because you moved em to the wrong spot.
Raid leader: You are the voice of the raid, really. Your job is mostly funnelling information that is brought to you by observation and input from your AT leaders. It's stressful, and speaking from experience, it's oftentimes a place where you feel as though you're supposed to have all the control, and instead you have nearly none. Sometimes you're in constant tell hell; others it's as if everything around you is running itself. So instead of trying to define the position, I'll point out the most important aspects:
1. Think fast, and trust your commanders. Keep an eye on everything, but don't try to do everything all yourself, because there's too much going on. Any person that's led a raid can tell you that nine times out of ten, they're too busy with one thing to do another at the same time, and nothing ever happens in a convenient order. They'll also tell you that if the other AT leaders weren't doing a hell of a job controlling their groups, the whole thing would be lost. Adjust the whole raid as you would a single team; when hami aggro hits the blanket, move the PA drop the same way you'd call for a tank. When you're getting griefers dragging monsters into the bubble, get the targetter to switch to the monster and watch them melt like butter. The biggest thing is to forget how many people are individually pulling together, and remember that it's a server effort: The server is a hell of a team, and they're all with you.
2. Don't be a hero. Sounds odd, huh? For many of us, we see someone in trouble, and we want to move to help each one. But in this case, you're in a position where sometimes a couple of hundred heros are looking to you for direction. You can't afford to put the individual in front of the raid; the raid has to come first. The consolation to this pragmatism is that it's not a matter of cold logic; it's a matter of trust. Remember that you're responsible for making sure that the raid succeeds: There are 200 other people out there whose job it is to back each other up at all times. Trust them to do their job, and focus on the process of getting to the end. They won't let you down.
3. Keep talking. ALWAYS KEEP TALKING. Compliments, observations, stating the obvious, repeating yourself, relaying messages from AT leaders, whatever. KEEP TALKING. A raid, as organized as it can possibly be, is still in many ways a chaotic mess. Your voice needs to be the single most dominating facet out there: It keeps focus, it keeps people informed, it keeps them involved. You will be mocked, teased, harassed, and worse: KEEP TALKING. If someone is giving you a hard time, it still means they're paying attention, and that's what's needed. You can't make people follow directions, but as long as you're making sure that the directions are getting out, you're doing the absolute best job you can.
Step Two: Staging
This is simple: gather all participants by AT, and get them organized into teams. There are a couple of specific benchmarks in population needed before it's really safe to head in to start. They are as follows:
6-8 Healers: And when I say healers, no offense Rads, but I mean Emps. If you don't have at least 6 Emps, your blanket's in over it's head for the most part. Rads definitely help with Radiant Aura, but it's not the foundation of the blanket. I know I won't start a raid without at least this.
4-5 Flying Illusionists: Either with their own Fly, or Group fly. Doesn't matter how they do it, but they have to be airborne, and you don't want fewer than this. This seems to be the sweet spot for holding Hami aggro for the most part: You can do it shakily with fewer, or rock solid with just a few more. 4-5, however, is the benchmark
15-20 Blasters: These are your meat and potatoes damage dealers when it comes to both mitos and hami. Without this number, it can be done, but it will take FOREVER, and there's less debt involved in waiting to make sure you have this many than in starting early
15-20 Melee: Melee are the guys that not only help drop mitos, but they make sure we can all get in there in one piece to start with. They clear the path that the rest of us follow, but they need their numbers too, because let's face it: Monsters suck. Don't want to start without them.
What about Controllers, you ask? Well, staging is about STARTING the raid, not finishing it. To START, we only need the illusion controllers mentioned above. To FINISH, you're going to need about another 15-20 of our crowd control specialists, too, at least to be secure. It's been observed that the average raid doubles in size about 75% of the way through. While it's not fun to bank on it, if we waited for perfection to start with, not only would we never get started, but we'd have some very bored people for a lot of it. Have faith that they will show, even if you don't see em to start. They'll be there when you need them
And what, oh what to wear?? Check out
Upsen's hamidon raid uniform guide , which was started here on Champion, and has been adopted by many other servers.
Stage Three: Blazing a Trail
When you've got your benchmarks, send the melee in to clear a spot to the EAST side of Hamidon. Why East? Two reasons. First, it's the closest side to the entrance, which means minimal monster involvement. Second, hami's mitos always spawn in the same place, and the East side has a blue one(electrolyte) that's always one of the closest to the edge of Hami. It's a perfect entry point, and it's served us well

At the same time as the melee enter to get monster aggro and clear space, the illusion team moves in to get position over Hami and to the WEST of him. Once there, they wait til the raid leader gives them the signal, and then they start dropping PA.
The other AT's move in approximately a minute after the melee does, to assist them in killing, and try to keep them in one piece. 60 seconds is a long time in CoH, and it's plenty of time to ensure that the monsters will be focused mostly on our tanker and scrapper friends, and not on us poor squishies. It's also a short enough time that we can get in there after them and buff them so they can sustain holding aggro
Stage 4: Attack!
Once space is clear, the bubbler will turn on Dispersion Bubble, and the heal team will begin providing that lovely green glow that sustains us through the fight. Everyone gathers into the bubble, and the targetter targets that first mito (usually that aforementioned blue one). The raid leader calls for the PA drop, the bubbler moves to target, and assuming people are following directions, the raid moves with the bubble. The raid is on, and from here on, it's a matter of sticking together, moving with the bubble, staying on target and listening to instructions.
Stage 5: Aggro lockdown
Once a nice, wide stretch of space has been totally cleared of mitos, the raid leader should send a regen scrapper to the middle of that wide space, and get him to taunt Hami aggro to him. The PA team should move to surround this scrapper with PA as well. This system provides much more stable aggro management, but is not feasible until there's enough space that the regen isn't going to get owned by mitos while standing there. IMPORTANT: THE REGEN SHOULD NOT BE DOING THIS UNTIL THE RAID LEADER CALLS FOR IT. I can't stress this enough. If you're a regen, and trying this while taking mito fire as well, get out and wait. By default, you're going to be as far from the raid group as possible, and that means that if you fall, it pulls an emp off the line to get your [censored] back up and moving. The raid group needs all avaliable emps in there, and if you're getting yourself killed, it's not helping with aggro

Stay back until there's room made for ya; it will make life easier for everyone
Stage 6: Pull out, Regroup, and slap Hami
When the mitos are all gone, the raid pulls out and regroups. Generally, this is done to the north, but that's mostly a matter of convention. Regardless of direction, clear out any monsters there, and regroup the raid outside the bubble. Once regrouped, the melee lead will lead all the melee through Hamidon to land a single hit on Hami, and then pull through to the opposite side and gather. This is done to ensure that our hard working melee get an enhancement drop, even if our numbers are so great that we need to ask them to stay out of Hamidon to cut down on lag. This should only take a minute or two; it's the melee leaders job to get them in and out fast, and so far, we've had some great melee leaders
Stage 7: Hold me close, don't ever let me go...
At this point, controllers and defenders ONLY move in and sustain the healing blanket while throwing holds on Hami. NO PETS OTHER THAN SINGULARITY AND DARK SERVANT SHOULD BE USED. I can't stress that enough. Other pets can yank aggro off of the regen scrapper that's still going to be in there holding his attention, and that can be disastrous. JUST HOLDS. Why nothing else? Two main reasons. First, since we're going to be damaging him, AND he can't move anyway, the only mez effects that would make a difference on him are Hold and Disorient. We want everyone stacking the same mez effect on him, and we know that Holds have visible effects and are a more complete lockdown than a disorient. So stick to holds, and holds only. It's worked pretty well so far, I'd say
In the case that controllers and defs can't stack enough holds to get him(and it will take a while to verify if this is the case), then BLASTERS with holds should move in to hold. If THAT doesn't work, then and only then should scrappers and tanks come in with whatever holds they have. This sequence is dictated ONLY by the raid leader; don't assume that if he's not held yet that that means you have to pitch in and help if you're not a controller. Sometimes you're going to be adding more lag than you're helping, and that's a problem.
Stage 8: Beat him like he stole something
Once he's verified to have been held, the blasters move in and stay at range. They shouldn't bother sniping, because the bubble interrupts the snipe, so stick to your bread and butter attacks. For most raids, with our average numbers, this is all it takes: The blasters will whittle Hami down rapidly, with minimal lag to the control team, and therefore minimal risk of the dreaded mito spawn. The fewer the people in Hami, the better, considering our turnouts, and blasters are king when it comes to damage.
If the raid can't deal enough damage with just blasters, or blasters are helping to sustain the holds and can't risk breaking the sequence to attack, then we call in the scrappers and their criticals. This is a big decision, because that many toons crowded on top of Hami is lag city, and can be hard to deal with. However, it's been done more than a few times, and it's worked when neccessary. Again, the fewer toons the better, but sometimes the blasters just aren't enough. This sequence extends to tanks as well, when the scrappers are yet not enough, and in at least one case where our numbers were extremely tiny, we had to call in not only all the scrappers and tanks, but we had to have the controllers drop pets to get over the damage hump. The point is that when it comes to Hami, lag is the biggest enemy, followed by his damage resistance. We only risk increasing the first when we just can't overcome the second any other way.
If Hami breaks loose of the holds after 50% health, the raid is doomed. Why? Because he'll spawn a yellow mito for every hero in range, and that's simply too many to cope with. We tried once. It didn't go well. So please, don't skip a hold for ANYTHING. Blasters, if he starts firing on people again before he hits 50%, STOP FIRING. It's better to let him heal up and start over than to kick him past the mark and be destroyed utterly. Keep him locked down, and it should be smooth sailing; slow and steady wins the race
Stage 9: KILL THE BUDS
When Hami dies, he'll spawn a bud for each person in range. For crying out loud, please kill them. If even one survives, we can get stuck with no Hami for hours after that last one is hunted down and killed. So save trading time for after the bud killing, and everyone comes out happy
And that, ladies and gentlemen, is that. Hope it helps

-M