Did the same, GRGRGRG. Tried blue, its too much movement, too much dps lost, too much movement for healers.. Proper cooldown rotations on rampages and its win !
We kill green, we go in front of red for rampage, then spread out. Kill Red, go in front of green for rampage, then spread out. Blow BL when 6th head is dead. Then its chaos and focus boss .
Healers call what cooldown they are gonna use so we minimize wasted CDs.
Whats helped us a lot is beeing really spread out, so minimizing the poison nova damage (because its you're close you'll take loads of damage), and having people placing cinders on the edges, not on the middle.
GL