I published this as a work in progress here:
https://www.thingiverse.com/thing:3715296
I'm using Fusion 360 to design with the hobbyist license (free, at least for now). I'd much rather use an open source program like FreeCAD however I'm still learning FreeCAD and am a lot quicker in Fusion 360 so 360 it is for now... I mention this because the Fusion 360 files are on the Thingiverse listing too (in Files).