Equipment isn't important. If you're full on the Crystarium then that is more than sufficient! The most important thing is that you take out those four magic casting things on the sides, and do it very very quickly. You probably noticed that they cast stronger and stronger magic. Once they get to those -aga spells you're pretty much smurfed if you haven't taken out at least three. Don't take time to buff until they're gone. Just COM/RAV/RAV and then RAV/RAV/RAV, occasionally throwing in a medic. Once you've taken those things out, it's much much easier. A sentinel won't be necessary if you're quick enough. I typically use Lightning, Hope, and Vanille for this fight.

Good luck!