@dc42 I consulted with the odrive developers, and they said that the step pulse interval was 2 microseconds, and all other values could be zero, So my values now are T0:2:0:0 I tested this witha couple of test prints, and it seems to be working good now.

I would be interested to see him test the 2660. They run well past the 500 rpm or so he's getting with the 2208's or maybe the arduino is just running out of snot. I was getting over 1800 rpm, accelerating 1.5 kg of tungsten ballast (w/ diagonal moves) on my test rig at high acceleration and 18k mm/m with Duet Ethernet set to 16x interpolated.
https://youtu.be/g2fO7k3WzwU

Thank you Sir