Jeeper, that will round off all the sharp edges, and not polish the inside corners. You may also enlarge the tumbler hole, I doubt it, but it's possible.
How about filing and rough sanding/stoning and then give a final blend in the tumbler? You might get a nice soft look. Fit a plug for the tumbler hole so it gets no abrasion. Fill the screw holes with modeling clay. i'm not recommending this as a procedure, but if you're bound and determined, plug them holes.
Acer