I had just made a 2 box guide when i found yours, so i will just add it on to your as a reply
Guide to Dual Boxing
WHAT is Dual Boxing
Dual boxing is using 2 computers (boxes) to play 2 characters (on 2 different accounts) in a MMORPG at the same time.
WHY Dual Boxing
Dual Boxing allows you to level 2 characters at the same time. (instant doubling of your leveling time)
Dual Boxing allows you to earn more XP per mission (even faster leveling)
Dual Boxing allows you to pick your teammate for the best synergy of powers. This allows for faster elimination of enemy, selecting higher difficulty rating, less character death and debt, even faster leveling. On a properly selected combo of ATs and powers I have averaged less than one death per level and have had a run of 10 levels without a death of either toon (set on invincible)
HOW to get started
Dual boxing obviously costs more as you need 2 computers, purchase 2 games and 2 accounts. For me it was no problem as I already had 2 computers capable of running the game and since this is my main source of entertainment and I spend over 40 hours a month playing it is more cost effective than renting or going to the movies.
Once you have the equipment, the games and signed up for 2 accounts you are ready to go. Be sure to set the screens close to each other so it is easy to see both at a glance. Also have each keyboard and mouse next to each other so you can reach from on to the other easily. Chose one computer/account/character to be the main toon (leader) and have that computer/screen keyboard/mouse directly in front of you. I then prefer to have my sidekick/partner computer to my right.
Log on and have your characters meet up. I usually start the 2 characters I am going to use at the same time, so I have them meet in the tutorial. If you have 2 existing characters move them one at a time (easiest) to a common location.
There are several important key binds to make you life much easier. Go to menu and then options, then key commands. This will show you a list of key binds. My preferences are
(in order from top down from the menu)
Auto run h
Follow f (this is the preset, I am just making sure you know it because you will be using it a lot)
Target nearest enemy r
Target farthest enemy y (this is useful for controller placing an AoE debuff so you kill the anchor last)
Target nearest friend g
Target previous friend - v
I found these to be the most useful and best position to minimize hunting for the right key on the SKs keyboard. Use the same on the main and the SKs boards.
Macro/powerbar button positioning on the Sks keyboard is also important . I generally put attacks at 1,2,3 and holds, buffs, heals, etc next, with travel power toggle at 10.
Tactics
Once your toons are in the same location have them team up. If they are significantly separated in levels have the lower one SK up to the high. If the level is 2 or 3 below the lower player will benefit from more XP if he can survive.
The have the SK/partner target the leader (g) and then set to follow (f). You will be using the g/f button combo a lot.
This activates auto follow AND auto target.
Auto Follow makes getting around easy. You will soon learn how to avoid common follower traps. The sewers are the worst for this. The leader needs to pause in the middle or right before each door. Also take corners wide as the follower will cut the corner short/tight and tends to get caught or lag more. The worst situation is you enter a boss fight and the leader enters the room and the SK is stuck outside and is not assisting. You then spend precious time trying to get the SK in range and back to auto target and then you both go down real fast.
Try to take the same travel power or complimentary travel powers. It is possible to have the leader be the taxi and take the fast travel and then teleport friend. This can free up power slots on the SK to make them more effective sooner. At level 5 I always go to Kings Row and do the radio mission/safeguard to get the rocket pack ASAP and repeat again at level 10-11 to get the jump pack. With these 2 temporary travel powers used carefully I can avoid taking a permanent travel power until the mid 20s.
Auto target is so sweet because now every mob goes down twice as fast. If one toon is single target and the other AOE it is even batter, but more on this under AT/Power Combos.
Best AT/Power Combos (now this is the fun part)
All ATs and powersets have weakness and the best part of Dual Boxing is you can pick the partner to offset your toons weakness. These are a few examples of my favorite combos. Please add some of yours in your replies. I list them in the lead/partner format. Most of these combos can run on unyielding or invincible from lvl 12 onward. (at level 12 I get all my toons fully IO enhanced and skip the whole DO and SO process. At level 22 and 32 I upgrade them all again.)
Tank/Blaster
Now you are a Tankmage. Tanker leads, grabs the agro and the blaster kills them all. The tankers power choices at first should be his primary powers and slot them up first. His job is to grab aggro and survive. The tanker should pick 2 attacks only at first and save more until later. The blaster is good with Single target or AoE, and of course a mix is best.
I have Fire/fire tank with Fire/fire blaster mostly for theme, but of course this melts all before it. Ice/Em tank with Sonic/Ice is fun too. Be sure that each toon picks heal other and then say to your self who needs a healor?
Scrapper/Controller
My Favorite combo so far as been a Katana/Regen scrapper with a Fire/kin controller. The Katana attacks have +def for you and def to enemy and all this is nicely boosted with Kins Siphon power damage boost and Speed boost to increase the recharge rate to buzzsaw After adding the fire imps the damage becomes crazy. Regen has a built in endurance enhancing power so I never have to stop and rest. The Fire/ also has some nice AoE controls (flashfire and cinders) to help keep the incoming damage mitigated. The trick is picking the right powers and slotting in the Fire/kin to keep the end usage low so it does not slow down the Kat/regen by having to stop and rest.
Defender/defender
I have a pair of Empath/sonics that have too much fun. The negative resistance of sonics stacks nicely with 2 of them. Then you add Fortitude on each other plus all the heals and you are approaching tank mage (massive ranged damage and you can not be killed). Make sure each toon picks all the leadership pools ASAP to maximize the pseudo tankmage phenomeon.
Mastermind/corruptor
What does every mastermind want more of? More pets of course. After level 6 the corruptor partner/SK is like a little assault bot. Why wait until the mid levels to have all that awesome fire power.
Mastermind/mastermind
This is a real test of who is the MASTER mastermind. Controlling that many pets is a mental workout. I have a Bots/FF and Thugs/dark combo. The FF keeps the defensively weak thugs alive longer and the thugs damage is awesome, add the dark debuffs and control and you are small army of invincible super killers.
Brute/Corruptor
Similar to Tank/blaster
Please add more of your combo ideas!