1. Holy Paladin, pop wings during the transition up top, the tank healing is very stressful. Get ready to use bubble DS when the tank is at half health and you get Mark of Combustion. You won't have time to heal yourself and the tank. At top, if a Mark of Combustion target is at half health, it's better to delay the cleanse and heal the mark target up to full than to cleanse the person while they are at half health. The dot from the mark after the cleanse is not trivial, especially if the shadow group happens to momentarily out dps the top fire group. Play it safe and top off the mark target before you cleanse them.
2. For our 10 man kill, we went 3.5 healer. Ideally the .5 healer should have been a boomkin, but we made due with an enhancement shaman. During phase 3 - unless your DPS is absolutely outrageous and you can 4 heal this fight - it is better to have one of your DPS in the fire realm NOT DPS and simply help heal. This is because, you will have 2 tanks and 3 healers - which means you have a surplus of 1 DPS.
We were wiping at sub 10% 4 healing this fight (meeting the enrage) - to correct this, we lusted during phase 1 and the holy paladin solo healed phase 1. During phase 2, we had 5 DPS down in the shadow realm to push into phase 3 asap.
We also kept our fire realm tank and healer (Holy Paladin) up top, our tank was a druid who could battle rez just in case someone brain farted during phase 2.
The transition requires everyone in the shadow realm to stop DPS, and the Holy Paladin to pop wings to heal the fire realm tank.
3. Have your .5 healer - boomkin or enhancement shaman do nothing but heal up in the fire realm during phase 3. If a DPS in the shadow realm dies during phase 3 due to an imbalance of DPS between both realms, the .5 healer will go down bottom and dps, otherwise the .5 healer/dps heals up top. Likewise, if a DPS in the fire realm dies, the .5 healer will then switch to dps to keep dps between both realms even.
This is a very unforgiving fight, if a DPS makes a mistake and dies in phase 2, you will have a very hard time meeting the enrage (which is what happened with us for a night and a half), if the healers don't babysit the marked targets correctly - your DPS will whittle down and the DPS between the two realms will become uneven - and will lead to a wipe.
Good Luck to everyone working on this fight, we found it to be challenging and frustrating at the same time - when the boss finally died, we were very much relieved.
