I have repaired maby canopies, but never been brave enough to
attempt a replacement of a bubble.

A friend has just replaced the bubble on her glass glider.

Canopies are moulded specifically for the frame they are to fit.

On glass gliders screw are normally used. but the canopy is
bonded to the frame using a high quality, one-component
polyurethane adhesive-sealant.

My friend used a product called CARBOND.

An internet search shows Carbond 940FC product details and data
sheets.

I would add that my friend had the help and advice of an
experienced inspector/engineer not only to ensure success but also
to ensure she had the signatures when the job was complete to
ensure the glider was airworthy.