I have a cee Bailey 20" screen on my 09. It works pretty well to cut down wind and buffeting up to the high 80s-mph. Even higher if tuck in behind it a bit. It also makes it easy to ride with my visor flipped up, which is something I never did with my modified stock screen setup.
If I had to order another one, I'd probably go with the 21" just to have a little less turbulence along the top of my helmet.
'18 Versys V1K
'09 Versys 650