The wing tip lens material does not cut like the canopy plexiglas. It melts with a Dremel cut-off wheel or sanding drum. The best way I came up with to cut it was with a Japanese pull saw. Then, trim to the line with a sharp block plane. There must be an easier/faster way, but I couldn't find it. These lenses were a slow, tedious process to fabricate and fit and they still did not come out as well as I had hoped. I am not too thrilled with attaching them with only two screws, according to the plans, either. Good luck.
Miss March 2020