I like the Third Eye glasses-mount and have used them for many years. When the joints get a little loose, they can be tightened by jamming them together. I may try that epoxy trick, thanks!
The closer the mirror is to the eye, the smaller diameter that will give an adequate field of view. For this reason, I prefer the glasses-mount over the helmet-mount mirrors.
Third Eye employs people with intellectual and physical disabilities, so buying their products also supports a good cause.