I have to say I am finding this an extremely frustrating fight. I'm level 32, and can't keep him from healing, and can't kill him fast enough. I utterly despise the fact that a game where you can depend on careful thinking and strategy suddenly devolves into one of having fast reflexes, and constantly re-loading saves until you get it right. I might add, I felt exactly the same way about the Mario-Brothers jumping puzzles.
I don't want to try, try, try again until I discover the trick. It's not fun, it's frustrating.