Never used carbonite before but I would never ever use a quest helper mod while multiboxing (if 5 wows on the same PC) as they are all super resource hogs and some are known to have memory leaks.

I'd rather just leave firefox open/minimized on thottbot.com and open it as necessary (which is what I do while questing).

Also if you're not using X-Perl or another unitframes like that, you really should get it! I just installed x-perl a few days ago and don't know how I lived or PvPed without it! Makes it MUCH easier to tell if your guys are in range, what buffs/debuffs they have, their cast bars, their target-targets, etc.