The ballast IS the external resistance.
OK, understand spring loaded IGN SW.
Parts: Get a externally resisted coil I linked. Get a Ballast I linked. O'Reillys.
Wiring: IGN SW start terminal to S term on solenoid. IGN SW run terminal to Ballast. Other side of ballast to coil pos. R on solenoid to coil pos. Batt to batt terminal on IGN SW.
No R terminal you say? Run a wire from start term on IGN SW to coil pos. Another way to describe same wire: Wire from S term on solenoid to coil pos.
Keep the Start to S.
Should be no other ignition wires. May be charging wires and sometimes the big battery lug on solenoid is used to power other components.
See 1953 truck/car schematic for charging wiring. I think you and I agree not to wire all that until you get the ignition working. You can charge your battery with a battery charger while doing this stage.
Power for ignition components on the schematic comes from/thru the ammeter it seems. I would not supply power that way. I like: battery to starter switch with a *fusible link inline. What *they are, and how to size them, is all on Google.
I don't like ammeters or wiring to them. Using them as a hot terminal block is a bad idea. Use a terminal block and use a voltmeter.
Also it is very important that all components have a fuse, or in the case of bigger battery supply wires, a fusible link.
The coil will get hot and the ballast will get hot. Normal.
It looks like your 6 volt starter takes a "saddle mount" solenoid. I do not know of a 12V solenoid that fits. I'm sure someone knows. It's good to do but not necessary. Your 6V solenoid will work. As Jerry says it may not hold under many cold or hot starts.
Don't throw away any starters or solenoids. The starters are probably only available rebuilt and the core charge is $100+ !!!!
Good luck Tneely. You got this. You have kept your composure thru your trial by fire from us old snowflakes.
