I fought him at level 58 and died a few times. I just made sure Squall had his HP and Str maxed. I used Hero to avoid the 1 hit kill attack. I just need 1k kills, 100 draw points and to finish the game and I'll have that plat.Hmm, trying Omega Weapon at level 60odd didn't seem to be a good idea, had no trouble with the rest of the game, so figured I'd be ok.
Just that left, 1000 kills and finish the game for Plat for me. Now, if I could just get Selphie to learn The End...