Wow, lots going on. Now I will start with the fact that I have run the Pertronix I in my Mustang and Cougar since it first came out using the stock coil and wiring. There was no 12 V going to it at the time and the very old instructions make no note about needing 12V. The cars ran just fine for two decades. Since then every car has been upgraded to the II using a Pertronix 1.5 ohm coil and a full 12V (actually more than 12V) to the unit via my installed relay setup. Only the truck doesn't have the relay installed yet since under the dash the resistor wire was plugged into a pig tail coming off the ignition switch. I simply unplugged it and installed my own 12ga wire direct to the coil. One day the truck will get a relay to bypass the ignition switch completely. I use standard Autolite copper plugs gaped at 0.40 and they run clean. Voltage to ignition runs close to 14V which is what the alternator system puts out when the engines are running.

Below the relay system in the Cougar. Two for headlights and one for ignition. A fuse box is mounted above with blade fuses. This setup is in the Cougar, Mustang, and Park Lane. The truck will be next to add the ignition relay. The Polara has relays forward for the headlights only. Ignition runs the other way from the starter relay so I use a wire with an inline glass fuse to power the relay which sends 13+V to the HEI ignition now in the Dodge. All Pertronix II, 1.5 ohm coils and Autolite copper plugs at 0.40". Timing at 12 degrees ( 289, 390, 410, 360) for all except Cougar (302) at 15 degrees with a total of 36 degrees all in by 3000 rpm max. Cougar came from factory set at 10L on the distributor plate unbeknownst to everyone when tuning back in the 70s and 80s at 6 degrees initial.

 

The instructions don't, but the Pertronix helpline guys seem to always recommend full voltage for the Ignitor I when practicable. Transistors usually have a pretty wide voltage tolerance once it meets the minimum threshold but excessive current will torch them pretty quickly. That seems to jibe pretty closely with the Ignitor experience. Sometimes I'll read claims that a generator charging system isn't suitable for the Ignitor, running the same module for 20 years and it's never missed yet.