You cant boost and still get the triple xp. If anyone in the group kills gray mobs, the extra boost does not apply. You have to run with the booster out of group, which means no instances.

I'm just gonna dual box a couple sets of toons on a 6th account, and xfer any toons i create off of the account after 90 days. I guess I could 5box and just leave one of my main accounts out for the time being. But with 2 of my toons getting xp at a much higher rate, they would quickly out level any other toons, so it would only really work for a few levels, unless I have tons of alts spread throughout the level range. I'm just gonna dual box as many toons as I can in the 90 days, and spread the toons out to my existing accounts. Then my main account gets "free" levels to spread around, so that'll be fun. I'm going to have a LOT of alts above lvl 30 pretty soon...