Has anyone "made" a new canvas for the early Devon (two part) poptop? If so, I would really appreciate confirmation of the material measurements. My old canvas is so far gone I can't get any useful measurements from it. Looking at the rivet locations on the poptop, it looks like the bottom of the canvas is smaller than the top?? Or is this just Devons tolerances of "to the nearest foot"? Just going to replace it with flat canvas.