Hmm, trying to time medica to go off after a big attack sounds like trying to be proactive like sch. You risk wasting the spell and the MP. Whm is reactive. That's why they get all their cure bombs. Earlier when I said that in order to heal like a sch, you can't think like a whm; well the opposite is true as well.

Now if later in the game there are instances where two big attack come back to back, I can see a whm trying to be proactive and time the medicas. If such instances exist, I'd hope it's in an 8man where both whm and sch are present.