I have no experience with windshields-- well, other than taking a 15 minute slow ride on my cousin's touring bike, many moons ago.
Is the idea that you actually look at the road through the windshield, or do you look over the windshield for most things you want to view, and you would only look through the clear plastic if you were looking at something very close to the front of your own bike?
Is the windshield's purpose to basically big be a giant fairing, but one that you can see through when necessary for maneuvering at slow speeds in parking lots etc?