I've been watching videos on this phase and guilds seem to be doing it differently. Most logs I've seen have shown guilds using only 6 healers. In the videos I've seen, some have everyone just run around the outside and move in for the (dispellable?) Frostflake. Others show just the melee with one mobile healer and the rest stacking inside by Hagara attacking the crystals at range. Is this what I think I'm seeing or is that too much damage to heal through? What seems to have worked for you?