As for stopping power, the Kawasaki Vulcan Potable LT braking system includes Single disc size at the front and Closing disc size at the rear. The Vulcan ENA had a very twin cc engine, six-speed transmission, and belt final drive.
The space between the top of the headlight and the bottom of the shield lets in a fair amount of air, but you can only feel it with your hand back to about a foot or so from the shield. I don't feel much if any turbulence or pressure on my chest when the shield is in the low position.
It seems to provide a little protection on my arms and shoulders.
Seems like my arms are just at the edge of the wind blast. Next I put the windshield in the highest mounting position.