Rememeber me? Here's your stragtery!
Mostly everbodies right Skytiger92, Start off with Lulu, Wakka, and Yuna. Attack the head with Lu's spells, Wakka's blizball,or you can attack it with Yuna' aeon, Valefor.Because if u don't attack the head, when it moves supspionly (i can't spell right)after it's next turn it will cast an attack called Venom attack, to recover from this just use an antidote or Yuna's esuna spell.(if u learned it that is)You'll know when the head's dead because it will turn gray. After getting rid of the head, bring in Auron and Kimahri. Just switch out Lulu and Wakka. Keep Yuna for healing. Keep dircting Auron and Kimahri to keep hitting the arms until they're gone. Then direct your attention on the Gui (you know the part the arms protected from u?) and also the arms come back every third turn. If Lu knows any second level magic attacks USE THEM!!!! On the arms it will take care of them easily. The second time u fight the is easier. Seymour can basic handle this battle easily by himself. Just use his black magic on the monster. But just use Yuna for healing this time around and just tell Auron to keep attacking the arms let him handle the rest ok? I hoped I've helped you out some Sky! Good luck!