[JerryL]

I would say the weather strip adhesive would work well. I have used silicone adhesive sealant on a truck mirror and has held up for about 10 yrs I guess.

I have an early Durant mirror that was getting flakey on the back glazing of the mirror, this has also allowed me to pull the glass free from where it was glued, I am planning on taking it to a glass shop by work and have them cut me a new one.
I know you dont have the orig glass like I do but you may be able to make a pattern and talk to a glass shop.

Regards