Does that picture represent the 1/8" divinycell?
Beware usiing The Template in plan and elevation. You don't get the whole story.
Even this is non-canonical, the bottom of The Template should be at ground level. it's height is half it's width. But it shows that relatively flat New Beetle roof needs to transition to the crown of The Template. Matching the height and width only makes it worse. The forward edge should be curved instead of straight across the car. To overcome this you might consider the squircle:
As for the trailing edge, here's Colani:
