The way my guild did this was we would have everyone DPS till adds spawned. We would have 2 groups made up of shm/bard/rog/monk/zerk/ranger one group would do 20% of his life while the entire raid killed adds. once you got him from 80-60 the grps would switch then switch again once from 60-40, ect. Worked out pretty well for us for the most part. We didn't wipe to him that often. The only mob we really ever wiped to after being on farm status was Kerafrym and even then that was only the first 3-4 wins on him. Crystallos is pretty much cake with tons of easily attainable loot imo.