so far ive always asked for tips and hints in other threads, so for this FF ill just make a special thread for it

my current problem:
i am to face Seymour for the 2nd time. and he is pretty powerfull!!
it all went well at first. i encountered every attack with NulBlaze/tide etc etc. No problem!
but after a while he starts stoning my characters and it all went well becaus i could heal them from petrification fast and often got lucky becaus Mortibody did not attack the stoned person..
untill he smashed Yuna to pieces
after that i couldnt keep up anymore and he defeated me.

normally this wouldnt be a big problem becaus i would grind a bit and try again..
BUT i can not grind on the bridge becaus those machina have very hard attacks and they keep killing me.
besides that i really need Ability Spears.Yuna has 11 steps but i dont want to go any further with that without unleashing 3-4 abilities that i will have to skip otherwise.
i have bought Ability Distillers (i believe they are called) but i can not use them becaus i can not grind :l

any tips, hints and tricks?