Any Tips For An AV Arc?

I was recently possessed by the crazy idea to make a "take on an AV" high level arc, but I know little about such things. I haven't even been on many AV runs in PvE and none in MA (due to fears of insta-squish) so this is new territory for me. But I really want to do this arc (with a minimum of n00b-ery/failure) because the story idea has me crazy excited to give it a whirl.

I already have a few questions about such "challenging" arcs and I'm sure there's areas to consider that I haven't even thought of yet so feel free to pitch in anything you think might help me plan this out so it's not crazyCRAZY hard and yet not a yawner for you old hands at AV fightin'.

1) What about the hard vs. extreme settings for the AV? I'm guessing this is dependent upon which power sets the AV has, right? And follows the usual semi-rules about how certain power sets like Energy Melee make for ridiculous opponents?

2) The AV is going to be part of a custom group; if I set the lower teir foes for "hard" to give the player the full XP, is this going to be nuts for anyone but purpled-out scrappers or something?

3) What about allies? Not "SB meh plz!" buff-giving allies but co-fighters - are they usually welcome or ignored? My story might have room for one is why I ask, but they can just as easily be left out.

4) Perhaps I am just over-thinking this and should just dive right in and there's not so much to worry about?

Thanks for your time!

Stay away from the extreme setting on most defensive power sets. AVs with a self rez or insane tier 9s can easily make what would have been a challenging boss invincible for some people.

Also note that, if someone is solo (or maybe even duoing), an AV will spawn as an EB and be a total wimp, relatively speaking. The only difference betwen an AV and EB at that point is the AV gets the Purple Triangles of Doom (mez protection).

Allies are helpful, though support from NPC allies is iffy; they don't always buff when or how you'd like them to. And if the AV is downgraded, it'll make the fight too easy. If you do have allies, you may want to put a note in the briefing text (in another color) stating that there is an AV fight with allies and to adjust one's difficulty settings appropriately.

Best thing to do is have allies be optional (ie, not a required objective). If the story demands they be rescued or linked up with, see about making them boss-level helpers instead of EBs. Note that for some people, the "boss" allies will downgrade to LTs... who'll get squashed by a EB. You can ask people to keep "Bosses on", informing them that they'll have NPC help to rectify this.

First of all, how challenging do you want the arc to be? Do you want it to be doable by someone who solos on +0/x0, or do you want to give a level 50 IOd out the wazoo Scrapper a run for their money? You can't have both, unless you're relying on the Scrapper facing the AV as an AV and not an EB. This is without even bringing teams into the equation.

Extreme setting is a no, either way. I would suggest Standard, with additional powers hand-picked to suit the AV's concept and get the challenge level you want. Build Up, Aim, Rage, are a no (yes I am extremely biased and would like to see those powers removed from MA entirely) and certain other powers can be problematic; for example, Rise to the Challenge can make an AV that is easy for a /Rad Corruptor very difficult for a Thugs Mastermind. Mezzes can be shrugged off by any melee character but will annihilate squishies. Powersets like Energy Melee are among the least offenders; all they do is hit hard, which is easily mitigated through melee AT secondaries, inspiration use, and kiting.

Minions set to Hard: That depends on the powersets. Some powersets have powers like Aim, Build Up, Power Sink, mezzes, etc when set to Hard. Avoid those if you must have full xp. If the custom minions aren't going to see much use in the arc, I personally think getting full xp for them is a non-issue, and Standard or Standard+ is fine.

Allies. I don't find them all that helpful. They don't taunt, which is the big thing, so you can't use them to tank for a squishy. Many melee characters function better with the enemies grouped up, with powers like Invincibility, Against All Odds, and Dark Regeneration, and allies are terrible for causing scatter. Especially if they have knockback powers. An ally with a buffing/debuffing/healing set is probably the most useful, if you can get them to use it.

Finally, it would probably help if we knew why you were trying to make an "AV arc." Is it a "stop the supervillain's evil plan and beat him up" story? If so, the villain's concept should be your first consideration, and everything else is secondary. People who can't handle an AV will get a big orange warning before they start your arc.

A few things of note:

Fast Healing from either regen or willpower will give an AV 100% regen resistance when the purple triangles are up. If you make the AV willpower, you can add a higher degree of survivability without even resorting to rise to the challenge with fast healing, the auto +HP and resistance power, and the resistance and defense toggles.

Be careful with giving AVs nuke powers. Most nuke powers when put in the hands of custom critters will be treated by the critter as just any other PBAoE attacks. What I mean by this is, the AV will just use the nuke whenever it feels like if there is a target near them. The only exceptions I have found to this are Nova, Blackstar, and Thunderous Blast. These nukes will be used much in the same manner that AVs in the standard game will use them at 25% health.

A lot of melee powersets in the hands of custom critters act strange, with the AV picking one single target attack and spamming only it, and then occasionally using an AoE or Cone power, after which the custom critter will pick another ST attack and start using that.

Super strength, energy melee, stone melee, battle axe, and war mace all have incredibly hard hitting attacks. This isn't necessarily a bad thing. If the arc is planned for high levels, and the AV is meant to be a challenge, attacks like Knockout Blow or Seismic Smash are perfectly good attacks to give an AV. However, I agree with Eva, build up, aim, and rage are right out. AVs hit plenty hard enough and are plenty accurate without them, especially if they have heavy hitting powersets like the ones I listed.

Earth Assault is a powerset I'd avoid straight out. It currently deals far too much damage. I don't mean that in a "Oh no, my scrapper got oneshotted" kind of way. I mean the earth assault versions of stone melee powers deal much more damage than the stone melee versions of the same powers, especially in the hands of an AV.

If you want to completely forgo a defensive set, poison is rather nasty in the hands of an AV. It may seem a bit harsh to give a custom critter poison, but the Electric Assault/Poison AV that I made just as a test killed my friend's Bots/Traps MM that he solos AVs with.