In trying to get the forward canopy view pleasant from the cabin , I decided to seal the forward edge with Sikaflex 295. RV builders know this product quite well, some even glue the whole canopy with it.
I was given some leftover primer (the expensive part) and bought a cartridge of seal on Ebay. Here is how it looks from outside, which is not important as the fiberglass fairing will hide it. Tomorrow I'll check the inside.