I have a Memphis fats with Suzuki Marauder mounts on a SPeedmaster. It's my 3rd shield. The lowers are mounted at a close 1/8th" gap or less between the lowers and upper screen. I can see over the top of the screen by two to three inches. I have no wind or head buffeting at all, up to 100 MPH.
I had a great deal of head buffeting with the Memphis Fats until I put the lowers on. Perhaps the secret to success with the Memphis Fats is the lowers placement? Why that is, I couldn't tell you, but others have reported the same.
If it matters, I moved the driving lights forward on angle irons, as opposed to cutting the shield.