I went from a stock windshield to a 25" (plus 2" wider) windshield and I sure can tell the difference at 65-70 MPH. Getting pushed around a bit.
I have a Cee Baileys. It was on the bike when I bought it. I would like to get one that is at least a couple of inches taller. I think mine is about 25".I bought a 26.5 Cee Bailey to replace a broken Rifle. Then I replaced the 26.5 CB with a 25.5 CB for better visibility. 26.5 is as tall as Cee Bailey's go for the C-10 I believe.