Aloha Friends,
Most guys use a contour gauge to copy neck shapes.
https://www.lowes.com/pd/General-Too...SABEgKwe_D_BwE
However, what they never tell you is to
use masking tape on the neck where you're going to use the gauge - to avoid marking the neck finish.
I also had long-distance players/customers send me outlines of their hands.
And, in the final stages, I'd even overnight the whole neck to a player & have him mark the areas that still needed some final adjustments.
That way, they "own" the finished neck.
A Hui Hou!
alohachris