I don’t know whether this will prove useful or not, but there are multiple ways to attack the rotation axis math.
The Eggbot from Evil Mad Science labs uses “pixels” rather than distance measurements for the circumference. With 200-steps per revolution and 1/16th microstepping, you end up with 3200 pixels for one full rotation of the item. In Inskcape you then create a template that’s 3200 pixels long by 800 tall (driven by the possible swing of the “pen” axis), and you can plot it on any size physical object, no scaling needed for different circumferences.
I’ll keep you posted.
I’m still looking for CAM solutions… I just installed a trialof DeskProto, which seems reasonable… Fusion might be an option too, but I don’t like the subscriptions