priest healing questions

If the boss dies, overhealing isnt an issue.

The only 10s that you need 3 healers are multi-drake OS, and its helpful on Malygos, Sapp and KT. Other than those 3 healers is severe overkill if your healers have half a brain and decent gear.

Are they using mouseover macros or wasting time targetting and then clicking heals?

For the other discussion, Renew and FH have their uses. Healers who have a decent ability to "read" incoming damage should be able to make the distinction and use both to the best advantage possible.
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