My strategy includes kimahri and rikku as theif like people and use poison fangs galore. Then when rikku gets mix use frag grenade and sleep powder. at the beggining of battle have tidus cast hastega. Whe you run out of the three "use" items, switch the first of the two for auron and the second for wakka. hastega them and whail until he is dead. another good place to level up is in the chamber of the stolen fayth. I beat yojimo no prob. and the enemies there have great items.