I did a bit of experimenting when I got mine and found that at 6’4 with the std seat and bars my helmet was in clean air and the clocks took the pressure off the arms, put an ebay screen on and just got turbulance. After raising the seat effectively 4 inches with dense foam 2 inches higher that doesn’t squish to nothing and bar risers to suit I was getting pressure so fitted a smaller screen that is only a little higher than the clocks and am back to square one with my helmet in clean air and no wind blast on the chest, a 5’8 mate has ridden it and was getting helmet turbulance , so if fitting a screen one size doesn’t fit all and you need to tailor it to suit your height and riding position