I think you guys are making it too complicated :p
I use the numpad for all my healing purposes.
Keys, + {plus}, 9, 6, 3, . {period} are keybounds set to macros. In the macro I have it target party1, party2, etc respectively to the keys, and also have it do /stopcasting in case I need to start a heal right away. Then I use the other keys for my abilities.
Numpad 7 is Heal, 4 is Lesser Heal, 5 is Flash heal, 1 is Renew, and 2 is Shield. I don't use 8 or 0 since I don't have any other heals as my PvE team is only 24.
I do plan on getting an Xkeys pro since I'll run out soon enough.