Yup. It was a good idea to mock it up.
The layman would likely be bewildered to learn the amount of effort that goes into developing a one-off of this precision and complexity, regardless of having begun with some excellent resources and having had the time to work out, in your head, much of the design. Including some fair amount for (engineering, fabrication, assembly, testing...) time, plus parts and materials, the end result will represent a substantial investment. Besides ultimately having a working grinder you can be proud to use, your ROI is the many lessons learned, the knowledge shared and satisfaction of a job well done. But also savoring the entire process and making that richer by including interested others, here.
Billy--attaboy!