can any1 help me

on kh2 for the ps2 im at the point where you go to The world that never was. not a ? about how to beat xemnas ok. the ? is when i go to twilight town to struggle with the characters the promotor keeps telling me "you dont have enough experience to fight seifer" and im like at level 60+ shouldnt that be enough or do you have to beat hayner a lot to qualify to fight seifer. now onto the next ? do you really have to have ultima weapon to beat sephiroth? ive seen a video on youtube and the keyblade the person uses is oblivion and they have the beserk option on. i have both the oblivion and the beserk option. if any1 can help please help because id really like to get jiminy's journal done. i can do the rest after you help with these ?s

forget the 2 ?s i did it. i beat sephiroth and did the struggle. i found out you have to beat hayner 10 times and setzer 10 times to get to him. and sephiroth well its a long story. basically i had elixirs and kept using them when he said "desecend heartless angel" and i was at 84 mind you. but man was he tough. when i got down to his last bit of health he almost had me with that move again but i pulled it off. i was mocking him, saying "ha ha sephiroth not so high and mighty now are we" anyway im gonna watch him and cloud face off. thats what you get if you beat him and talk to cloud they fight each other. whoops spoiler sorry.