Jim, it's been some time, but I dug up my notes and here is what you can do (at your own risk of course
)
Raise VGN1 (#2205) speed loop gain until it just about vibrates, then back off a little
Raise VIA (#2208) speed loop advance 500 at a time, do test cuts and when it's getting good, change +-200 units until perfect
You can have the machine interpolate a circle with a nice feed, spindle stopped, listen and feel for any groan, vibration and hiss.
tweak until is as good as it gets.
You'll probably have some jittere in the 45 degree area of the circle, you can turn on adaptive filtering or jitter comp (#2227)
then it's a matter of trial and error.
You might like to decrease in position width too (#2224), it's usually set at 50 (0.05mm), but cutting it too much will produce clunky movement. Mine is at 20 and it works ok.
Please note that #2227 is set with hex!