I can speak to the Windjammer question, been riding behind mine since 1972 February when I rode it home in the snow and below-20 degree temp: it was an 80 mile trip for the first time with a 'windshield' and the very LAST time I toured without a Vetter.
Several things are involved, one of which is the vertical angle: look at pix of the Vetter and the Goldwing fairings and you will see what I mean. The more rakish angle of these systems push the air up over your head (and sideways away from your body as well) and slip through the turbulence: it starts working at 40 MPH and by 100 MPH, if you ride behind someone in front of you also with a Vetter, falls back on the 'pocket' at that point. I used to beat my brother up on his 500 (with a Vetter) when we'd be out sparring with each other: I'd get in front of him at about 90, pull around him and get about 10 feet in front, which would rattle him but good!
My wife also attests that between 45 and 55 the backseat ride changes from buffeting winds to a quiet, still pocket. She usually sits back there with a paperback book pressed up against my back, reading while we cross places like...Kansas....