I am 6'1". I got the 13" and had to exchange it for the 11". At the lowest point, the 13" top edge was dead in my line of sight for the road--drove me nuts. They do reccomend the 13" for those over 6', but it just did not work in my case.

Yes it does help with the radio---a lot.

And yes, the wife says she can tell a lot of difference when I just tilt it forward and raise it just a inch. Combined with the hand wings and there are bunches and bunches of adjustability on how much or little wind you want.

I wear open face helmets and love to tinker with it depending on the weather.