Williams optics 9x50 finderscope base

[5ash]

I have a SW ED80 with a Williams optics focuser . The 9x50 finderscope base fits into a slot on the focuser and is held by one finger screw.i find that the finder can rock up and down though slightly .have any other users of this mounting method observed similar movement and is there an easy fix. I have thought of drilling a small hole in the base of both the holder and finder base and inserting a small cylindrical lug to mate both more closely or drilling from the side of the holder and inserting a second thumbscrew into a threaded hole in the finder base. I would rather a simpler method other than permanently epoxying it in. Any suggestions appreciated.
Philip

[Den]

I f I am understanding this correctly insert a plastic spacer under the slot to tighten the space , perhaps from plastic milk carton or thin sheet metal. Hope this helps.

Den