Beautiful design! I made a few mods that made it easier for me to print (I generally abhor support.)
The crank shaft and cams have a square shaft. The base has been changed a bit to accommodate the square-to-round bushings.
The rings themselves, as well as the upper and lower registration brackets should be sourced from the original as I only included the modded stls in order to keep it simple. Thanks for including the STEP file! That made things much quicker. I've included mine as well.
The make in the photos is scaled down to 75%.
I use 1.75 or 3mm filament to attach the crank knob. Just form a rivet by melting the ends of a short piece of filament. a little sanding and/or filing may be needed to get everything moving smoothly. I also used a dab of hot glue where the upper and lower brackets fit to the base.