“There was a second wire off the starter circuit that bypassed the resistor and gave it the full 12V to insure you got a good spark while it was starting.”
Actually the reason the ballast was bypassed during starting was to apply full battery voltage - but since this was during starting, that voltage was much less than 12 Volts...so the voltage to the points was about the same whether starting or running (i.e., with the ballast in line).
Understood. But it wasn't necessarily "much less". If that battery was in good condition and the engine already warm it might only drop off a couple of volts. How much it dropped would depend on how good the battery was, and how much load was on the starter. Bigger engines and cold/thick oil would add to that considerably.