Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:5127620.

Remixed this, fixed the spacing for the mounting holes (I think it was 0.5mm short) and added an x-axis cable chain attachment.

Worked with a $10 dual gear extruder that I bought from eBay (not sure of brand).

The original creator wasn't kidding about it being a tight fit.