Ended up using the Neutrik port dimensions and this image to make some estimates:
[ATTACH=full]222372[/ATTACH]
If the port on the left is 22mm wide, I estimate the hex nut (flat to flat) is ~12mm, the middle metal part is ~9.2mm, and the center "button" (in white) is ~6.4mm.
Looking at the specs on the Eaton part I linked to before, the dimensions are 14mm / 11.68mm / 7.87mm
The ratios between the parts are about the same too, the metal "center" is about 77 to 83% of the face to face nut width, and the button is about 67 to 70% of the metal width
I'm currently looking into threaded metal rods that are hollow, then I could put a nut on it and maybe insert a wooden dowel or something.