The mopar reluctor setup is more a spike than a nice square wave like an optical pickup would give you. It has both positive and negative voltage components. As for it being a leading or trailing edge component, that's not relevant to the distributor, it's relevant to what ever the distributor is triggering. I do know if you get the two wires from the pickup swapped going to the stock ECU it will change your timing. As for what your Pertronix wants, well I think you figured it out in spite of their tech support.

Pic of typical magnetic pickup signal