We found that if one of the orbs on the ground is absorbed it gives several stacks to all members of the raid of the same type. To maximize dps we had all dps get the same essence and our healers would have 2 different and absorb the orbs for the raid (this was a very easy to fight to heal in 10 man). Also switching essences does not remove your stacks. We used this to gain a raid wide 100% damage buff very quickly during the fight where we used hero on our first one. During the heal it was simple enough to just have all the dps switch essences to break the shield and interupt. The twins can be tanked relatively close together and can be moved around the room to position your raid closer to the orbs to change essences quickly.