I haven't really done much with the Priest.
As far as macros go.
I have Renew and a Penance/Flash Heal x3 sequence, cast at the target of the active toon, for healing toons not in my group/raid.

I am using repeater regions, with IS Boxer, which covers 99% of my healing.
Grid is set alphabetically, so its the same on every toon.
Top box is always the same for every character.
The team with a dedicated healer (disc priest), only broadcasts clicks to the priest.

Alt Left - Renew
Alt Right - Shield
Ctrl Left - Penance
Ctrl Right - Flash Heal
Shift Left - Pain Suppression
Shift Right - Prayer of Healing
Forward Thumb (mouse) Button - Holy Nova



I'd be interested to see what you come up with for a click macro.