seriously, the 04 250 basket will not fit your 500, however, I think there were older 250 that might like maybe 88-89 ish, of course they are probably toast by now and wouldn't do you any good. Clutch baskets are hard to find other than OEM, there are some Talons in the UK and maybe a few Pro X's around, don't think you can get Hinsons any more. Usually when you find a used one, its used and probably not much better than the one you have.
good luck finding one.