Bill,
I think it's very valuable making Zone Rulers, especially for beginners learning to visualize print values. The fact that you point out, i.e., that the Zone Ruler steps are not even, but follow the combination film and paper curves, is something that really helped me when learning years ago.
BTW, I made rulers for most my different films and development schemes (at least N, N-1, N-2 and N+1). I followed the directions in the White, Zakia, Lorenz "New Zone System Manual," which doesn't require step wedges or densitometers (or plotting for that matter). For me, the strictly in-camera and visual approach worked well.
Best,
Doremus