I use a similar approach, atm i'm only tri-boxing until I get my new pc (hopefully soon):

Acc 1: DPS (all toons 60+ with 2 80's)
Acc 2: DPS (Level 80 boosting toon, transfer to acc 1 when 3&4 all 60's))
Acc 3: DPS (All toons 40+)
Acc 4: Heals (All toons 40+)
Acc 5: Tanks (Will be linked to acc 2 for RaF grind)

But as i'm going for one of each class on each account, I will have a large mix of toons to choose from eventually. Gonna get a PvE team to 80 first, then gear up and grind badges for heirlooms to make levelling easier for the other toons. I find putting all the slaves in my own guild much easier for levelling and storing items (Legio Altus)