I wish I could help more. Just had one delivered yesterday, $206 delivered thru EBay. It has the vent hole. It looks nice, but have not mounted it or tried it out yet.
Does not seem to be a lot of interest on this site for the VStream. Everone seems to like the Cee Bailey. I had one of those on a BMW, great shield. Never had one on a Wing so cannot compare the two. When I get mine up & running will post something on here.
I have the National Cycle VStream on my 89 GL1500 , when it arrived I was initially not so happy with it. It is of a different shape towards the bottom and not as wide as OEM. Also because of the way the shield is formed to make a V stream for air flow it caused some distortion toward the bottom of the shield. VStream is made with polycarbonate vs Lexan of OEM original and is more flexible than OEM and many of the other manufactures out there. Go to National Cycle web site and read The Windshield Bible. Long story. I am getting used to the shield and it's not terrible and I will keep it , doing it over again I would perhaps go with Cee Baily or Clearview windshield. JMHO , I really don't wish to disparage National Cycle because I do believe it is a good windshield. I ran through a heavy rain at Yellowstone last summer and it did seem to deflect a lot of rain away from me. One of my determining factors in buying the VSteam was saving a little money which if I recall it was somewhat lest costly.
I have had mine since Aug 2011, @30,000 miles now. I put it on for my cross country trip that ended up being 13,500 miles, 3 1/2 months so I rode in 110° leaving and really liked the vent being up about 5" higher than the markland that was on when I got the bike as it put the airflow up at my face, where I could feel it. Made a difference in using the hydration vest and neck wrap in the desert.
Car Toad mentioned the flex, yes it does and at 75 mph and above it flexes a lot in high wind so I'm not so keen on that.
Other than the flex at high speed and wind it's a great windshield.