1. Charge up Lulu, Wakka, Tidus, and Auron's Overdrives
2. Move out
3. Tidus Casts Hastega. If you don't have it, caste Haste on TIDUS FIRST! Proceed with hasteing everyone else.
4. Use Cheer, Focus, Reflex, and the thing Wakk has that raises accuracy. Multiple times if you like.
5. Sinced you upped accuracy, slow evrae.
6. Proceed Lulu to use drain Fury.
The missiles will help a lot.
7. Just hack away with Lulu and Wakka (I tought tidus drain so...)
8. When he moves in, swap Lulu for Auron, and use aurons Overdrive and Tidus overdrive, and Wakkas overdrive.