So I installed the windshield yesterday. Very easy. I had to remove the 3 bolts at the front of the roof so I could slide the hinges in their holes. I took my time and it only took 30 minutes to install.
Very, VERY, nice poly windshield. Looks and feels like glass.
Now, riding with it...remember that I ride in central Florida and it was stupid hot today...like the rest of the county. Oh, I should add I have a 2019 Defender xmr - completely mechanically stock - tires and all.
Rode with it 1/4 locked. Drove over my usual terrain about 10-15 mph. Hard surface, little bumps. Windsheild was perfectly solid. It let a reasonable amount of air in but the air followed up the windshield against the inside surface ... it didn't blow out towards the passengers at all. With the heat outside, it was uncomfortable for the passengers without air in our faces. I will be installing a fan/fans shortly to hopefully resolve the air flow and excessive heat issues.
Next, I rode with windshield up, same speeds, same terrain. Not as stable as I thought it would be. The shocks keep it up nicely but the windshield did vibrate quite a lot. I was worried the hinges would eventually fail with the vibration. The shocks that hold it up simply pop onto the ball pins. I was worried that any excessive amount of vibration and they may pop off the ball pins. Maybe not but I felt it could. I am NOT recommending that you ride with the windshield up unless it's a smooth road. Also, remember I have the xmr mud tires and that could be part of the vibration problem. I'll have to try again on more sandy environments and see if it's better
Bottom line - I love the windshield. It looks and feels like very good quality.
I wish there was a way to have it lock open maybe 1/2 way. This would let more air in on the super hot days.
More testing to come.