Customizable Router Engraver

Engrave a design in a printable plaque with this Customizer. Design a plaque, draw a path to cut in it, and design a virtual router bit to do the cutting. (The bit is designed by rotating a cross section, just like my chalice lathe.)

Lag Warning!

This thing makes extensive use of the hull() command to compute the shape of the path cut between successive points. The Thingiverse Customizer docs discourage use of this command just because it is pretty slow. So, be advised it may take a very long time for the Customizer preview to update after each change. I welcome tips from any OpenSCAD pros on how to do this more efficiently.