Slave Y Axis in bCNC or UGS or ...

I am going to build a C-Beam XL as my first project. Mechanical bundle is on order through the parts store. In the meantime I have been research options for all of the electronics. I originally settled on using a Raspberry Pi with a Protoneer CNC hat connected to external drivers. I then ran across a GRBL board that Kyo had created to interface between the Pi and a Gecko G540. I would use either UGS or bCNC as the control software on the Pi.

So the missing piece I have not been able to...

Slave Y Axis in bCNC or UGS or ...