Renew from all of them, will be a good... top up type spell.

You might want to pre-bubble the tank and/or team, when there is AoE stuff.
You could also pre-buff the team with Prayer of Mending.

With a glyph, you will be hit capped for Smite.
And Smite will heal the lowest health party/raid member for a decent amount, with talents.
Smite spam will be the simplest method to passively heal.