I'm finally getting back to troubleshooting.
I ordered one of these:
https://www.realfixesrealfast.com/short-finder.html
Basically an automatically resetting 10A circuit breaker with a Gauss meter to detect current.
I clipped the CB to a test light to have a visual indication of the breaker tripping and replaced fuse three with the set up.
I reconnected the stator and VR to the circuit, but left the pink wire from the dash to the fuel sender disconnected.
When I turned the key to ACC, the test light lit, but the ignition light did not. Also, the CB did not trip, suggesting it's either way more than 10A (15A fuses blow in fuse 3), or faulty. I turned the key to "on", and again no ignition light and no CB trip. I started the car. The ammeter was charging, but no tach. The test light remained lit, although it seemed a bit dimmer than when the key was in the on or acc position.
I reconnected the pink wire to the fuel sender and no change--no acc or on ignition light, car started fine, and ammeter worked. I disconnected the pink wire again.
I inserted a 10 Ohm shunt resistor in parallel with the ignition bulb Bob sent me. The purpose, according to Bob, is to add current to the VR energizer circuit guaranteeing actuation.
I removed the CB from fuse 3 and repeated Patrick's test with the auto-reset CB + test light jumper between the ACC terminal and the outer (double green wire) tab on the ignition light. Both the ignition light and test light lit (although dimly).
I put everything back together, put a fuse in #3, turned the key to acc, and the ignition light illuminated. Turning the key to "on" and the ignition light still lit. Starting the engine, the tach worked, the gas gauge moved off E, the ignition light was not on. Everything seemed to be working correctly.
I reconnected the pink wire to the fuel sender and the 15A fuse 3 blew. I disconnected the pink wire, replaced the fuse with the CB and test light. No ignition light, no tach. Started the engine, the CB did not trip, the tach didn't move, the ammeter showed discharging, but not charging.
I'm now thinking I have two issues: 1) a ground loop or short in the pink wire to the fuel sender, and 2) an intermittent VR.
Thoughts?