Dave,
I would say nearly 45 deg. But you may pick it better off the photos.
I used the rubber under the windscreen plates but put the additional sealant in. A low cost build tip.
I found at speed the screen did move slightly and heavy rain was getting in. Put the sealant in and found that it stopped that occassional drip of water.
Just experiment. The sealant sealed the rubber down onto the body before I put the plate on.
Sounds like you have it all sorted. Again good luck with the build.
Cheers
Bernie