it is hardly worth it. It cannot be done with the top in place. The labor and materials to r&r the top and sew in new plastic windows comes dangerously close to simply buying a new top.

BTW I got my top from Prestige and do not recall them offering glass windows. It would be difficult to impossible to stow the top with glass windows.

When you get a new top or windows if you choose, I find it useful to carry a baby blanket under the top for stuffing between folds when stowing. This will eliminate the folds rubbing together and will prolong the life of the top and windows.