This may be a little extreme but if you are set on keeping those mirrors this is what can be done but is a little crazy. I used to work in a glass shop and had the same problem on an old car I had so I broke the glass and adjusted the internal clamps and cut another piece and it was good as new.
sadly so mirrors have a thin piece of metal screwed in around the pivit ball that has to be hammered flat then put back but will end up bending again. A never ending cycle, you would be better off replacing them.
68 RS Ash Gold