One Leg Ballast Resistor or Two

I have a 1967 Barracuda with a 273. I'm converting to Electronic Ignition and have the Mopar Performance kit sitting right in front of me. Since my wiring is pretty dry and brittle, I figured a new wiring harness was in order.

Back in October I ordered an original harness for my car modified for Electronic Ignition. It arrived today and I noticed it had the connectors on it for the dual ballast resistor.

I have the single ballast resistor in my kit. I'd like to stay with the single ballast because I want to keep it in the stock mounting location. It currently mounts in a little spot over the left inner fender back against the firewall and I don't think I could stick a dual ballast in that spot. Also, since my MP EI kit came with a single ballast, I know it will not use the red/green wire on pin 5.

What do I need to do so that I can use the single ballast resistor?