I don't know If this is any help, but I am Dual Boxing since yesterday as well.

I still got a lot to learn, and realized boxing toons isn't as easy as it would seem like! I got 2 warlocks and have all the spells on the same spots. All pretty basic, I use autohotkey to send my commands to the non-active window. So far this works (although much tweaking is still needed).

The only moments I need to switch screens so far is to take quests and turn them in (or to loot items for a quest). I got free for all loot on so I can always loot.

There is off course the movement problem, where if i only turn aound to fight an enemy, my friend stands still facing the wrong direction, but other then that it seems to go well.

Dont got a clue if I helped! :P