Trusting a digital template for 30 vehicles? ...well....I'm betting you're gonna try one first!
If you have access to the same vehicle, why not trace your own?
I draw a 1" grid on some 4 or 6" premask, whatever it takes to encompass the curves, apply to the glass.....
draw or cut a line where the glass meets the gasket, remove and lay on your workbench. ( of course, you only need to do 1/2, right?)
Reproduce the curve in your design program, then cut or draw one on some scrap to see how it fits. Note the wiper path and any fasteners that will detract from your design.
Edit and refine the fit as needed....before you add the copy and/or print the graphics.