I'm 5'9, 31 inch inseam. I bought the madstad 20" figuring it would be just about right, sure it looks like a barn door but I knew the extra air behind the screen would help eliminate some of the noise as well.
I was on the edge of getting the 22 as I will only use this shield if I plan to take log trips so the wind doesn't wear me out, and it regularly gets to be nearly 90 when I'm headed home from work.
While it is certainly much quieter the air rattles my helmet and head, the only way I can get away from this is if I duck my head a few inches. I will continue playing with the angle and height to see if I can get away without adding anything extra on. Devising some sort of laminar lip may be needed but for my trip this weekend it will have to do and will still be much more comfortable than stock.
If anyone has a 22" madstad and wants to trade/try a 20" let me know and I'm sure we can work something out. I'm located in southern Indiana