The only way to travel!
I cut about 3" off the top of the windshield, so as not to have to look through it, and the wind bubble still was above my helmet.
Tell me about it...the windshield is WAY to tall. I was going to cut down mine too. I want to order a new one with the vents and cut this one down to around the top of the fairing and use it for summer. Still working on hard bags.
FWIW, I'm 5'11" and I cut mine off to about 19" height, and that put the wind boundary layer just above my helmet. At that height, I am naturally looking over the top of the shield. Below that was almost completely still with the vents open. I eventually just removed the vent pop outs totally, even for the winter as they made the inside air much quieter. Made almost no difference in the rain.
I determined how much to lower the original shield by riding at around 60 mph, and moving my left hand up and down above my forehead to see where the boundary layer was. It was about 3" above the top of the helmet, so I then cut the same amount off.
You can easily cut the shield with sabre saw, using tape to protect from scratching the surface.
You can also hang the shield upside down and treat the cut edge with a chemical (I can't remember the name right now) to smooth it out like factory finish.
You can use a common door knob hole saw ( 3 1/4" I believe) for the vents which fit perfectly with the original pop outs.