You've got it basically correct. Current limiting in the Gecko determines torque. I limit torque during tightening, and run full torque for loosening. I loosen 1-1/4 turns, and on tightening I go 1-1/2 turns, stop, the go an additional 1/4 turn. In most cases, the first move will stall near the end, and the second is just ensuring full tightening torque is reached reliably.
There is no reason this would not work just fine with a G203V. When the drawbar stops, the Gecko will limit current, and should not fault. It will only fault if the motor outputs are shorted.
Yes, the air cylinders provide enough down-force to pop the collet free of the spindle. Wouldn't be a workable PDB if it didn't. There is no "hammering" motion, it is simply about 300# of down-force.
Regards,
Ray L.