I always try to make sure that I'm always ready to switch back to healing ASAP, so I favor the stuff that are instant-cast. I find it's all situational, really. If we are running into three or more enemies, I'll take the time to throw up Shadow Flare first, then heal whatever damage has happened, then throw on Cleric Stance and go Areo - Bio - Ruin II. If everyone is fine and no serious damage has been taken, I move onto Thunder - Bio II - Miasma - and another Ruin II. By then there is usually damage needing to be healed even in the more bulky of parties, so I'll throw off Cleric Stance and go back to healing.