I was still having problems with getting a linear, low RPM response from the BLDC ESC.

Re-flashed the simonk firmware on the ESC. I reduced the stop pulse width to 100us and disabled auto-calibration.

I spent far more time figuring out how to use my new no-name programmer than anything else...

Settings I used are in tgy/tgy.asm in the github repo.

This gives me a much larger range of pulse widths I can send it now.

The valid PWM range (at 400Hz update rate) for a happy ESC on startup is now 0.025 to 0.037, it starts spinning at <5% above that, and has a pretty much linear response for the range I need.

Good enough.