I initially used the standard maslow calibration (estimating left-right motor distance, top beam height, and sag correction factor). Then I had to cheat the Distance between motors because the top center positions were too low.
On my maslowCNC frame (11.5 feet top beam), I had to extended chains, and set chains length through GroundControl.
Here are my physical settings:
Distance between motors: 3501 mm (the real one)
Motor offset height: 618 mm
Extend chain distance: 2000 mm
Chain length: 3450 (that is what can go beyond the sprocket, but Ihave more behind it to connect loose chain pulling mecanism)
Rotation Radius 138.14mm (I use the ring kit)
Chain sag correction: 12
Now did you see the improved Holey Calibration beta test? If you do want to try it, I invite you to post your question on that topic.
This one will tune both chains tolerance, distance between motors, and motor offset height. It includes chain stretch correction and does not need chain sag correction (but you have to measure the sled weight and enter it to ground control.)