Alright, I just gave it a try with the picture of your truck. Here it is:
I seem to have the same ? as last time, it looks like the truck isn't
perfectly level (The rear of the truck being a bit too high, which I suspect is why the rear portion of the roof doesn't seem to fit the template as well as the previous picture), and I'm sorting of shooting from the hip at the point of max roof camber again, my eyes are playing tricks on me a bit I think. So this one is likely not dead on, but very close.