New glass is great and is a real nice finishing touch to a project, but it just has the wrong contours. I have used all kinds from non-tinted to factory tint to smoked from many different suppliers. The biggest issue I have found is that the new glass is not cut properly but even more so, a lot of them are curved wrong. The original glass is convex with the center portion higher than the ends if you run a straight edge across it from the outside of the car. I have found that a lot of the new glass is actually concave with the center area lower.
I have a set of brand new, never installed, been on my shelf for 2 years now smoked '69 Camaro door glass wrapped up and ready for anyone who wants to bend it to the proper shape. All it should take is a torch and a hammer. Heck.....it works on steel