After a week of fiddling, tweaking, figuring, and mangling, I've finally determined that my timing was set correctly when I put the engine together in the first place.  A weeks work, and nothing has changed mechanically, but I now have 100% confidence that my timing is set correctly.

I drilled out a spark plug and used some 2-cycle oil in a clear hose.  (Didn't have any ATF handy, Lynn.  But the 2-cycle was dark blue.)  I quickly found the null point, and was disgusted with myself that the timing gear was off by 40 DEGREES!!   How could have have screwed it up THAT badly?  I was in the process of deconstructing the timing gear, when I decided to check one more time.  I hope this nugget save someone a week in the future.

If you use the air pressure method of determining TDC, there are TWO (2) null spots for each rotation of the crankshaft.  One will be where the apex seal is visible, or close to being visible, through the spark plug holes.  That isn't the one.  You want the one where the rotor recess is at the spark plug hole.  The former is MUCH easier to find than the latter.

Once I figured out this little brain fart, it was quite easy to see that the plugs were firing very close to perfect, 22 degree BTDC without ECU control.