"Mass" Raid or Group Healers?

Just interested in theory, if you had to mass healers that would heal whole raids via multiboxing, which would it be?

I'd imagine probably not Holy paladins or Discipline priests.

RDruids -> spam HoTs per target? Rshaman -> spam chain heals? Holy priest -> spam prayer of healing?

Thanks.

All of the ones you mentioned would rock in it although I think dudu would probably win seeing as he has both wild growth and individual hots. He also isn't bothered if he needs to move and cast.