wkehrman said:Alternatively, you could put the arcs on the cover plastic and have some sort of compass point that would turn. Leave the back end of the mount open, put a notch in the front end of the counter and a tab inside the mount. The counter should line up with the tab to keep things properly aligned. Unfortunately, I lack the craftsmanship to make this.
I think I see what you're going after with a 2-part piece. I was thinking a one-piece design, and you would use something handy like your fingernail or pencil to mark the maximum turn at the marked arcs and then turn the piece up to that far.