Epoxy will adhere to the hardened vinylester with no problems. The assumption is that you first sand the surface. Unless the surface is damaged perhaps you could give it a light sanding and just varnish it? You can experiment on the bottom. As far as stripping off the vinylester and leaving the glass ?? is that what you meant? Just sand the surface with some 300 or finer grit. I would use wet sanding paper - no dust, less clogged paper and faster cutting.