You only need to remove 0.5mm of material at a 90deg angle to the flat of the mount.
A few wriggles of a flat file against the frameline actuating surface will do it.
I cannot post an example right now, but do not file as described in the above link. It will work, but is way ott
When using the flat file tape over all surfaces not wanting to be marked. Tape makes a handy stop point on your filing surface also.
Tape / mask off the rear element and surrounding areas so that no swarf enters the lens body / focus mechanism.