Well I have a dedicated, tank, 3 dps (mage, hunter, cleric) and healer, currently heals are from a cleric, highest full team is only level 22. Tank is a warrior/pally build and Iron Tombs sucked at level 20 when I tried it. I felt healing the tank was a real struggle, BUT I was coming from WoW and nicely geared tanks and knowing that game pretty well.