What ballast resistor do you use for the aftermarket electronic ignition system?

First off....YES, I did do a search of this. The info that I'm seeking wasn't clearly listed.
For years, various vendors offered a factory appearing electronic ignition conversion kit for these cars. It featured a distributor, a 2 pin ballast resistor, a 4 pin ECM and a small wire harness with the plug for the ECM.
What happens when you need to replace the ballast resistor? What is the OHM rating of that 2 pin ballast resistor?
Looking at a troubleshooting book that I got from @halifaxhops it shows the stock 4 pin dual ballast resistors and states .5 ohms. Is it fair to say that the 2 pin ballast resistors should also be .5 ?

ECM chart.jpg

I had a ballast that reads:

HR 29.JPG

I bought one that the NAPA guy claims is correct for a 1970 Charger with a 318 and points ignition:

IMG_E7821.JPG

Where do I find a .5 ballast resistor?