I have a very tall and wide shield from Show Chrome ,can't recall the dimensions and I am at work now.It ended up being a Little to tall, didn't like looking through it. So I shaved a slight radius in the top center area just below my line of vision. Saw a shield on the INTERNET years ago made like I cut mine keeps the noise low along with the wind.
I ahve the same one, I think. 4 inches wider on each side and a couple inches taller. It's too short for me (I'm 6'3") and most of my head sticks above it and I get lots of wind noise. I'll be switching to the 19" F4 next spring, I think.