A yes learning curves. Wonderful thing and Yes, John S would be cussing you out Jazz. Jonathan, you volunteering to aid in the mission of the Linux CNC side of things? These days for me CNC is mostly design as current location doesn't allow me to run my gantry router due to the locals have very very sticky fingers and crow bars. Though the learning curve is still fun as working with scanning as part of work and with both OpenScan and FabScan Pi (I hate software programming).

Looks like a very in depth project Jazz. Of my two cents I would try to keep the 4th axis if possible.