Just wondering...

[Lyrica_Ashtine]

Eh, you guys aren't really elaborating why the OP should use Aero or Aero II at all.

SO let's line up the potencies:
Stone: 140
Stone II: 170
Aero: 50 potency + 150 over 18 seconds (total of 200 potency)
Aero II: 50 potency + 160 over 12 seconds (total of 210 potency)

So potency-wise, Aero and Aero II has more potency than Stone II in a single cast. All spells have the same GCD too (be it instant-cast or hard-casted). Naturally you'd want to get these out first while you're still in cleric's stance as it has slightly more potency for a single cast.

Edit: I forgot about Holy :P
Holy isn't worth the potency vs MP cost. It also takes slightly longer to cast while it doesn't have that much more potency than Stone II. It's good as AoE, however. But for single target it's not worthwhile to cast unless you need that stun effect - Which may be hard to time due to animation delay on the effect.