Ideas for 13" covers on larger wheels?

That's really cool waggin, thank you! Two questions:

- which model Centerline 15"s are under there? Looking around, they make a lot of different styles/shapes.

- once they're on, how do you get the painted covers off? Is there room to pry them from the front like normal, or do you have to stick something through the vents in the rim and push from the back?