Thanks for the comments all, I think it will work now after tons of messing around. The problem was something with the VFD power supply not cooperating with the C11G, or just not working properly. I tuned the output to be very linear with the 10V from the power supply, with in a few tens of mV, stable and nice. But with the spindle on the voltage was all out of whack, generally ~1V higher than with the spindle on, but with varying wildly +/- 1V or so of where it was with the spindle off. Both tests were done with the VFD powered on but just with it in the off state for one. The funny thing was that the 10V was stable, at least with a digital volt meter. I was afraid to hook the scope up to it to see if it was rippling but it looked solid because I don;t have a differential probe and am not sure what those lines are relative to earth.
I even measured the pulse widths and plotted the frequency output VS speed and everything looked fine. Finally I just hooked up a 12 supply and all seems to be working now, although I have not thoroughly tested it yet, tomorrow...
Dustin