The backers are virtually invisible. Just position them and drill your holes so the top of the backers are even with the top of the plastic front "beauty panels".
Yep, I am 5'-8" and shrinking, and in the hot summer rides I don't get any airflow with the V-Stream - I only get a bit of airflow in the top helmet vent, and on my gloved hands. In warm weather I put the stock windshield on, and I only put the V-Stream on when riding double or the weather cools down. The V-stream does a great job of keeping the buffeting wind off my wife when we ride double. I am wondering if I can put some of those round vents into the V-Stream like the old Vetter fairing used to have.The only disadvantage I have found with the V-Stream is that due to its 4" taller height in the summer its a lot hotter to ride behind even when in the lowest position. I get zero airflow over my chest and all the upper vents in my riding suit are worthless. I am only 5'7" tall so taller riders may not have the same problem. This summer I will probably put the stock windshield back on to improve the airflow when commuting and use the V-Stream the other three seasons. Fortunately changing out the windshield on the NT is really easy.
If you do decide to cut a rectangle hole in your windshield, be sure to drill all four corners before cutting. A round corner is less likely to crack.The V-Stream is incredibly efficient at deflecting almost all of the wind off rider and passenger. This summer I got quite hot several times riding in 90 degree plus heat. I ride with the shield full up all the time. Very, very quiet. I have SERIOUSLY thought about buying the whole vent assembly for a GoldWing (about $150). With some creative effort I wonder if it could be cleanly mated to the Stream? I think it would fit. My only worry is: would the screen be dangerously weakened by cutting a rectangle big enough for the vent to fit. If it didn't work, well I have done far crazier things. Opinions please....