You really do have your healer 'hang back' quite a bit compared to non-multibox play, until instance bosses my healer (if/coh) is rarely used for anything other bad pulls or after combat life tap + prayer of healing regeneration.

That said, its good to start doing things right from the beginning no matter what your setup is, to get transitions fluid and when you get new spells to be able to use them incrementally.

It seems that the chain-spells and high end talents are real game changers for you class, so much so that you really don't seem to spec away from the nuking spec. But even with hunters, mages, destruction lock in groups you really just blasting mobs and they rarely touch you after a pull and often die with excessive overkill in damage.

Likely you want to develop that signature blow cooldown, kite the mob though a train of totems for the spell cooldown, recast spell that just cooldown routine for mobs when you can. This versus a stand and deliver approach that would require a lot of healing.