you can use the one with the positive feed to retard and hook it to the starter solenoid wire, so when the starter is cranking the module will drop timing to make it easy to start.OR hook it to a WOT switch to retard at full throttle like you were thinking
You could use the ground controlled one by simply using a relay on the same sterter solenoid wire, Or WOT switch, just use terminals 30 and 87 for a ground path instead of power.
