You could try a f r special, they are a lot better than the knock offs and only about 80 dollars. They will also accept a brass block and have a steel locking nut.
I found the Allen screws are way too soft and the heads strip on the copies, as well as the locking nut stripping threads.
I haven't had your problem with the knock off which is still on my SV1, have you got any spare springs from old kits to swap out for the ones you have on there?