Dave
Hi
Sounds like you are getting good advice here. The only thing I found when fitting my screen was it was an advantage to open the bottom hole up on the posts.
This allowed me to move the screen back and forward until I found the right angle (look).
Between the top of the windscreen and the back of the body between the seats is 36". Does that make sense?.
My photos will give you an idea of the rake I used. I can move the screen about an inche forward or back.
Just one other thing... Once you fit the screen put plenty of "Silastic" or similiar sealant around the posts where they go through the body. Then put the cover plate on whilst its still wet.
Drops of water down those posts make a real mess in the footwells in heavy rain.
Have fun building
Cheers
Bernie