The angle is 43*
That makes the windshield weather strip lay all across the same distance and the windshield frame actually does not touch the body.
In some cases there are stay brackets in the center from the body to the frame.
Besides all that the buffeting is much less than with any other angle.
However the modification of the angle on the FIA cars came with the long straights like on the Nurburgring --- But they got in trouble for that. It is known as the “cheater” tilt-back windshield. Faster car but puts more strain on the driver.
Nurburgring
Targa Florio
