What we did was to have everyone in raid solo soak it. Our warrior could even solo soak it with shield wall, die by the sword, rally cry +( priest shield). If there every is a problem that someone gets it twice thus cant solo saok it, make sure to call out on your teamspeak so ALL can stack asap.
Rogue = cloak ( will be up for second transition)
paladin= bubble (with unbreakable spirit CD will be up at second transition phase aswell)
mage = iceblock (coldsnap to have it for both transitions)
warrior = read above.
druid = symbiosis on mage/hunter if resto, symbiosis on rogue if oomkin, symbiosis on priest if feral
warlock = dark bargain, followed by glyphed Healthstone + unending resolve
Shadowpriest = disperse
disc priest = i dunno? pain sup + shield + barrier? (not sure)
hunteR= deterence
Shaman = problem
dunno..we had none :/
DK = ams/ibf
So - hope for some RNG, incase shit happens stack up
If you have to stack up then -
What we noticed here was, DONT use any cooldowns. Only pop absrobs. No damage reducation. It seems (just a guess from what i noticed at our 30 wipes) that if someone takes damage reducation the damage will just go to someone else whos stacking with him.