Does the motor have jerky movement when it is not attached to your machine? The drive should be tuned while bench testing to avoid any mechanical backlash problems manifesting in the PID adjustment.
The trimpots should be adjusted by the position when you are looking directly at them from the adjustment side.
The holes on the PCB for the oscilloscope are meant to have a probe inserted and a ground clip attached to the GND holes by clipping it to the board. We will be popping a video up soon about how to tune the G320X and we will show how to attach an oscilloscope voltage probe as simply as possible.