The stat increases of Illumina are great, and 256 battles is not a lot. You get the cursed shield in Narshe, in another building, just like you get ragnarok. Honestly, get the airship, go to narshe and get mog. Go to the phoenix cave, put mog in a party with moogle charm, then the other 4(Celes, Sabin, Setzer, Edgar) in the other, get Locke, then get the ragnarok sword and the cursed shield. Equip the cursed shield with a ribbon on someone in your party the rest of the game, and trade the sword for Illumina. It'll be a big difference maker for everything in the WoR. Plus anyone can equip Illumina with a merit award on them. And you really should fight over 256 battles, at least if you never run away or avoid battles.

And to me, magic has never been my thing anyways. I started with FFI which was so limited in magic, I got a bad taste for it. Either way, I uncurse the shield more for how amazing it actually is, than for the fact it teaches ultima.

THE JACKEL