Verification, please?

canyncarvr said
Almost. During 'start', available voltage (battery, through a switch, through a bunch of wire) is supplied through the 1/2 ohm or compensating resistor.

Not sure why you say 'almost'. We wrote the exact same thing, unless from what you write here

canyncarvr said
A basic ignition 2-pin ballast pic is attached. Not what you find on a '73, but the wiring in question is shown.

and

canyncarvr said
During Run, system voltage to ECU-1 is NOT reduced. I could understand wanting to route the supply V through the resistor on Run because the voltage is higher, but that's not what happens.

I think I misunderstood. You were asking about the single resistor arrangement....and I was describing the dual resistor arrangement, hence my reference to the '73 wiring.

Ths MSD trigger hardly any current. There's a relay in the MSD to draw current from whatever you attach the ravy red wire to. That's one reason the old instructions suggest just attaching it to the original coil feed (which then sits outboard on an insulated tab). That way its easy to switchback to a factory ECU or points if the box failed for any reason.