They are close enough to flat that if I wanted to go concave, I would have plenty of surface area for double stick tape or even velcro, but I wanna go convex.
If you look closely, you'll see that I never cut the ends on the zipties on the painted cardboard grill block. It was never meant to last, but to see if it would be worthwhile making a more permanent block. This I will do. And there is clear packaging tape over the foglights.
If you look even closer you can see a few "aero-dimples" courtesy of the previous owner.