Don't reduce the expander ball, send the die back. They made it, they should fix it.
I'm not a big fan of Lee. Some of their stuff is fine, some just doesn't please me. Most of my die sets are RCBS, some are Lyman, a couple Lee.
There is no point to crimping .22-250 ammo. All that does is give you a way to screw up your ammo if done badly, and works the brass more than needed is done at all.
All else being equal (and it almost never is) bigger bullets tend to work better.