I beat it with 93% on the first try and my characters only at levels 56-53.
although i am kinda confused as to how easy Vegnagun was. there were fiends that were stonger than the final boss. the next time i play i think ima gonna go down to the level that has like 101 cloisters and try to beat that. and i have to get all my dresspheres at 100% too.
i also got the good ending. the one that has Tidus come back. I absolutly loved it!!! im so glad they brought him back at least for a lil bit. ima go back to playing X now too.
just thought id brag a lil bit : )