Many years ago I replaced the glass on my +8. I took it to a local g!ass shop and they cut a new one out of flat glass that was in stock for school buses. It was tinted at the top for the first 4 to 5 inches. They cut the top so I have 3 inches of tint. You should check for an industrial glass shop, they may have bus or lorry glass they can cut for you.
Make sure the screws in the frame don't go in too far, if they are hard against the glass it will crack from temperature change.
