@ntouched here’s an easier solution than 3d printing – just found this on the same bmcuser thread where I learned how to print rings myself. A company that makes the rings from high-quality materials at a much cheaper price than Duclos – https://www.cordvision.com/product/lens-gear-easy-install/
@ntouched – I used to have a set of Leica R primes. I ordered the Leitax mounts and had them installed professionally, then bought the step-up rings myself and 3-d printed focus rings. Decent-sized savings over the CineMod.