I just made 20 of these or so if you would like my artwork I would be glad to share. I used a 24 x 18 single sheet of coro to make these. The way to go on these are a cnc no doubt but in a pinch nothing beats a good old utility knife. I made myself a template with plywood and tried routing these back last year and it left the edges a little messy. So I switched to the blade method and it worked perfect. I had a sore thumb for 2 days but It was well worth it.