I don't understand why you're telling him not to cast PoM BEFORE the pull. By the time the pull starts, he should have that mana back and it acts as a buffer.
Anyway
PoM -> Chakra -> Renew -> Heal (as soon as he pulls) -> HW:S and then keep spamming heal, don't wait for him to drop below 50% then FH/GH, you should just use GH whenever it won't be overheal. Don't be afraid to use your mana.
If the group is taking damage, toss a heal on them, don't Renew (it's not very good ATM, with more haste it will probably be, but right now if it's not on the tank, bleh). Binding Heal should be used if you and someone else need healing, it's good on mana and it gives seren. stacks, which are always nice. If you really want to heal the group up, just cast PoH once, and your EoL/glyph healing should handle them. If they take anymore damage than that they're probably doing it wrong.