Level doesn't matter much, as long as you can survive dark matter. I always liked this battle, because of the sweet-ass backdrop. That is one cool circle he's got there.

This one isn't that hard. Whenever he uses a certain type of shield, use that type of magic. I think he drops his defense before he casts Dark Matter, so you should use Frog and Chrono to attack him then. I can't really remember fighting him, but just keep up your health and you should be fine.