Dear Pascal,
First I will gratulate you for your Hebmüller-Project. After the little shock, that we didn't get it, Christian and me think that it was the best choise to sell it to you.
Most of the convertibles got a new roof durint their life and often, the rear window changed into a bigger size. A few years ago, I found an original complete roof of a Hebmüller, which was stockted since the early 1960s. This roof had the origininal rear window inside - without any logos. It is now installed in No. 5.
For my project, I have to use a new glas. We have the luck, that Hebmüller used a flat. The factory who made the new glas is able to sign it with a "SEKURIT"-Logo. I think, that I will use it becaus it fits to the rest of my windows.