strike that i did end up getting 100% story completion after beating trema. it just showed at 96 percent when i saved at the save sphere before the musical puzzel in the farplane then when it went through the credits and the endings it showed 100% story completion and a thank you for playing i'm happy now hehe.
its not beating trema that adds to story completion it's going through via infinito watching all the boss transformation fights and so on. simply going through via infinito and completing all floors without skiping boss fight scenes will net you roughtly 1.8 percent. trema is just a pain in the ass that gives a nice drop item that addes to all stats. even though he is a pain in the butt to beat the item he gives after the fight is a nice one to have as an accessory
i didn't use soul springs nor did i have any in my inventory. i just had all 3 girls in mascot with break hp limit accessory on a few of them and kept hitting him with moogle beam and cactling gun from yuna and paines dress spheres and healed with potions and threw phoenix downs when needed with riku. it was a long fight but i got him just the same. oh i also had an accessory equpped that gave first strike as well.
To beat Trema I had to beat the game 3 times, in order to obtain 3 of the same item, the Cat-nip, it allows you to perform an 99999 attack when your HP is low, this item combined with the Speed Bracer, the gunner dressphere and the Highroad Winds garmentgrid in a Trigger Happy attack will destroy ANYTHING !
Equip this on every single girl and, with a bit of luck, you will defeat Trema in no time
Just check this video: http://www.youtube.com/watch?v=zxCVGgUsFKQ