This is Heroic right? Then our list as follows:
2
2
2
2 (or 3, depending on if I want to heal or DPS)
3
3
2
3
2
2
3
3 (or 2, we've done 2 before)
3
with a bit of gear you can even solo heal most of encounters even Durumu . You just need good dps and people need to move out of stuff and don't do mistakes. Also other raid cds are preferable. (talking about normals here, not HCs)
Check your healers HPS, if it is high, check why is so, if people are getting unnecessary damage, then that's a reason why you need more healers.
We usually 3 heal during progression, and drop down to 2 healers whenever it's highly beneficial.
Now that everything is on farm tho we 2 heal 13/13, except Megaera, (could 2 heal that one as well, if we somehow got our DPS to slack. Rampages every 30sec or so is not fun)
We 2 heal every fight except for Megeara. Progression I think we 3 healed Council, Iron Qon, and Tortos. Heroic of course.
we 2 heal everything in normal (me as a resto shaman and a holy pally) and some bosses in HC