Bypassing Ballast Resistor / Installing Pertronix Ignition

Agreed. Pertronix versions vary. I understand that the original Ignitor is a simple transistor switch, with no dwell control, so still requires a ballast resistor. It is similar to the 1970's Mopar ignition, though easier wiring than retrofitting that to a pre-1972 car if you use a ballasted coil. Ignitor II is more like GM's HEI, having dwell control and no ballast resistor. Ignitor III adds multi-spark and rev limit, at a much higher price.