Just looked at the new material I have used to make the port lights and it is just under 1/4" with the protective paper still on and it matches what I removed (with the exception that you can see through the new stuff). The polycarbonate I used was easy to cut initially on the tablesaw and then finish with the pattern following router bit. The plastics place I bought the material from says they use routers almost exclusively to cut these materials, which kind of surprised me. I would have thought the router bits would tend to burn or melt the plastic.
