I actually had the idea of getting a small lucite cutting
board from the Farm and Fleet or someplace and doing likewise.

Bill, can you provide details and tips?

The Jaspers are made for precision in 1/16 increments. I can
see that if the builder was working with few driver types that
some standard centers could be used without the 1/16
machnings. But when routing rabbets, those 16ths might come
in handy.