To make things somewhat easier, I completed the sidequest with those things who want gems. That places Ozma close enough for you to use physical attacks in case your MP runs out and you don't feel you have the time to restock. Which everyone surely knows by now. *A-HEM*
Then I levelled my crew up a bit (60-70 is super), beefing up Thievery as much as I can, and marvelling at how Dragon's Crest jumped from 7800-ish to 9999 before I knew what hit me. After achieving that, I promptly went up to Ozma, equipped what ability I thought I'd need (Auto-Regen among others, Auto-Haste if I can), and added some Shadow-absorbing stuff, just to be on the safe side (meaning: now that I've made Ozma keep his Doomsday to himself, at least THAT won't be the attack that gets me).
Then to the team: Zidane (duh...), Freya, Steiner, and Amarant.
Zidane for the obvious reason.
Freya for Dragon's Crest (9999).
Steiner for Shock (9999).
Amarant for Aura, Revive, Chakra, tossing stuff and the odd No Mercy.
Strategy? Bah! I say kick the ball! No real problem there.