I used my Fluke, and read 0.375v as the output of  TII as compared to the
0.4v with the RS analog meter.

Both TI and TII started out around 1.2v from ambient ~82f or so.  TII went
to 0.375v in about 4 minutes of operation.  The O2 sensor output varied from
~0.15v to ~0.75v.

At idle the O2 voltage did not seem to swing up and down, but stayed
predominantly about 0.6v.  This is where I set the AFM with the O2 sensor
disconnected.

Does anyone know if there are any absolute trigger voltages that the ecu
responds to?

Continuing to dig,
Joe