Not sure about the ballast resistor stuff, but would assume that if the resistor was bad, it breaks the path of electricity to travel to the distributor in order to start. The ballast resistor reduces the voltage down to 9v for the hall effect, that's all.
As far as the amp gauge goes, the weak link in them is the insulation wears out and short circuits. So, if it is giving you a problem, or, being as old as it is, with the battery disconnected, a large red wire (10 or 12 gauge) runs from the starter selonoid through the bulkhead connector (they can corrode and become weak at this point), then directly to the amp gauge with a brass nut on a stud, then the same thing on the other side to the fuse block for direct power (with and without fuses). At the gauge itself, it is metal, the studs have a phenolic (I believe) piece of insulation, which wears out over time and the red wire grounds to the gauge, thus the body, and shorts out the electrical system throughout the car. Replacement of the phenolic material with new non-metallic washers fixes the problem. If you still don't want to do that, simply take the two red wires, and use a small bolt in the two eyelet connectors together (so as not to cut the ends and solder them together), and then wrap with electrical tape (I prefer the cloth tape type, it doesn't get sticky over time) and the amp gauge will be bypassed.
