I tried to glue the rear window in place myself on my 54 Light 15 after it fell out. I ended up with the glue, putty, caulking, whatever all over the place including my hair. I then did it the easy way. I took it to a nearby automotive glass shop and they did it. It was easy! All I had to do was pay them, what could be simpler? The back window on my 49 11BL fell out the same way. Off to the glass shop, no trouble at all. Some jobs are best left to the pros.
I did see James Geddes do a large to small boot conversion at John Gillard’s a few yeas ago. If anyone can do it, James can.