the way I always do it....I put my "fast team" on...Yuna, Auron, and Rikku, you might want to experiment with yours but those are the ones who get the most turns per fight. Perfect weapons(I don't call the ultiment cause mine are more useful to me, i never use the ultimant ones) and ultiment armor(Auto-haste,phenoix,med, and of course break hp limit). Cast auot-life on everyone(be sure at all points of the game that you have auto-life one)be sure that everyone is 255 on at least strength. use quick hit everytime. its quicker to defeat him that way than magic and also its very strong against it. keep hitting and casting......oh yeah I've never seen 2 Armagedon attacks back to back and it does the White Spark b4 it can do Armagedon...after armageddon it has to charge up one whole set of turns..to kinda give you a time partern on when to hit and defend....other than that have patiention but its does give off good leveling up equipment (triple ap, triple overdrive, overdrive -> ap). oh yeah and warp shpere if you beat it.....I've never gotten an overkill on it. oh yeah and if you have master theif on your armor you get a warp sphere each steal.
