hmmmm... I don't know if this is a good bet as Omega's pretty beastly especially with light pillar, but Sephiroth is so powerful (even though he was really easy), moves like Supernova and his others and his power to just levitate seems so powerful in this. 1000 on Sephiroth, I'd bet more but Omega's strong too and his predictable pattern probably won't hurt him til later rounds if you're including it. In caser you didn't read my ramble:

29,000

1000 on Sephiroth