Gary,
I know what you mean, on mine just reducing the aileron travel took care of it almost completely, I still get a little binding on full travel, but nothing it can't tolerate for a short time.
What I count on is I almost never have my controls that hard over in normal flight. (never have in fact)
Maybe you need to in crease the allowable travel on the elevon some how? Probably not possible if it's already hinged etc..

Don't know what else to do!

Pete