Well we're on the Days forum, so....
-I always favored Cura over Curaga, more reliable.
-Wouldn't count on offense magic (which sucks in general in this game) due to the sheer length of the fight.
-Every level up counts, don't take off levels just to make room for something.
-2nd phase will be a pain, bad AI spamming the DM over & over, just keep gliding & wait it out.