Hi! I recently bought a Fortis Flieger 595.10.46 from chrono24 with scratched crystal glass and I'm going to try to replace this by myself. The crystals' material is in mineral glass but I will try to replace it with a AR-coated sapphire crystal (is this a bad idea?). Anyway, my main question is if there is a way to find out the size of the glass, without removing it first? I can see that the diameter is 36.5mm, but how do I know the thickness? Best regards Markus