I'm about 95% sure it's the Hall Generator in the distributor.   If I
hook a timing light to the spark wires and crank -- no spark.
However, if I hook a wire to the middle connector on the hall sensor
(as per Bently) and drag this wire across a dirty metal part
(repeatedly making & breaking a circuit) I can hear sparks and the
timing light starts flashing.

Kudos to http://thebuslab.com folks who were patient and helpful with
suggestions & parts.

Now I need a new distributor.    If any list vendors have a rebuilt
distributor for sale, in stock, and can send it fairly quickly
(fedex?) please contact me off-list via email.

thx!