Tuning G320x without oscilloscope - halscope?

Hi,

I'm attempting to tune a G320x (Rev6, the first release), driving a 170 oz/in continuous (840 oz/in peak) servo at 70V as a lathe spindle.
I'm trying to tune it 'by ear' as I don't have an oscilloscope.

I cannot get it tuned to get the servo running past 200-300rpm.
The servo runs at expected 4500 rpm at 70v connected directly.
Mesa 7i43 and 7i76 boards.

I bought a new encoder (AMT102-V) as the old encoder was 8192 count, and from what I found the G320x can't cope with that. The AMT102-V (set to 512 counts) at least allowed me to the get the motor spinning.
At idle, the servo behaves as expected - dithering between encoder positions and resisting movement. I can't get it to spin up past a few hundred rpm without faulting though. I've tried very slow acceleration and it helps slightly.

Is it possible to use halscope for tuning? If so can anyone explain what signals I need? I can wire the servo encoder to my mesa boards.

Help is appreciated.