This might a necro by me, but since I've healed the fight as both holy and disc-priest I'll offer whatever help I can:
Originally Posted by samskara
As a holy priest, depending on your healing setup you should probably be on raidhealing. Use CoH everytime it's up. It should top of some people, and possibly proc a SoL that you can use on a DPS who is going low or on the tank. You can also throw up renews on people if they havent got lifeblooms/rejuvs on them already.
The spell that was probably designed for this fight is Prayer of Mending. Since everyone takes damage, it will jump every second and ease your healing alot. Now, I usually put it on melee. This is just my thoughts about this fight (and might be a bad way to do it) but anyway, our raid is usually positioned like this;
Since the ranged can usually dodge Blizzard, that's not much of a problem. But if you get a blizzard like this;
The melee might have problem moving out since if they move back, they can't dps. If they move forward, they might be out of range for the heals. So, put yourself in a melee-heavy group, throw in a PoM and use Prayer of mending in case they are getting low. Oh, and remember the SoL'd flash heals on the people close to death.
Hope I was of some help atleast, good luck on Sapphiron!