I asked Pertronix the same question when I put an Ignitor unit in my 1948 M5. I got a 6 volt, positive ground unit from Bill Cathcart for the Champ 6 engine. Pertronix sent me a wiring diagram they worked out for the Packards with overdrive.
Depending on the vintage of your overdrive and the type of relay and solenoid you have, the exact wiring may differ. On my old-style T86-1D transmission, there is only the solenoid switch, no governor, no lockout switch. Pertronix shows adding a 7 ohm, 5 watt resistor to the circuit to limit the current draw through the Ignitor when the hot side of the coil is momentarily shorted. I found an 8 ohm, 20 watt wire-wound resistor in a ceramic package at Radio Shack for $2.29. I took a 1" wide strip of thin sheet metal, bent it around three sides of the resistor and left two tabs sticking out so that I could screw it to the firewall. It works great. It ought to be about the same for the 12 volt, negative ground unit, but you can always email Pertronix on their web site or call them.
'65 Wagonaire Commander
'63 Wagonaire Standard