[Tygen1]

Ok, here's a couple pictures:
The first is the Overlay on my car, just want to make sure I have correctly applied it. In addtion I added a red line to represent a 30 degree angle going back to intersect the Overlay. It's quite big!
The second is a "What if". What if we imagined a 15 degree angle down from the top of the rear glass, this is the blue line. What if we imagined a 12 degree angle from the top of the glass, this is the yellow line. The red line is carried over from the overlay. I chose the top of the glass because this is where the angle of the cars shape starts to exceed 15 degrees, the glass's maximum angle is 24 degrees. The reason I added these "what if's" is because it will be difficult to make the red line happen without damaging the car to support that big spoiler. Is is worthwhile to pursue anything shorter?

Additionaly my rear window is fairly well rounded. Check out the dew streaming down the rear window picture and the somewhat top view. This leads me to believe the air is pushing and wraping around the outside third of the window, but not really the middle third of the window. If I put on a spoiler, would it need to be tallest in the middle and taper down towards the outside edges?

Thanks for considering my questions!