It stalled out again today, and restarted after about 30 seconds and ran normally. The tach has been normal throughout. Other than that, there has been an infrequent miss or stumble that wasn't there before.

I tried wiggling all the wiring connections (distributor primary, power stage, coil primaries) with the engine idling. None of them made any difference. The power stage was cool to the touch after half an hour of driving.

I now suspect the Hall effect sensor, as it is subjected to heat, oil, and vibration, making it more likely to fail than the other components, therefore I plan to put on a spare distributor. I will post a report on how that works out.