We used a 4Grp + Tankport. I did a diagram to show, that it should be way better to divide the Healers not even on all grps but more like 3-1-1-4 (9 Healersetup):
The white Area is the Dragonpart, the grey Area is the Demonzone.White Dots are Healers, Red DD, Brown are Tanks (click to resize):
But basically i'd say you can't really plan it exactly like that, as different Portal entering Times combined with the Cooldown of the Portals (20s-25s) messes things up a little bit.
WWS Kalecgos Kill