Is the reluctor in a Mopar electric distributor a rising edge or falling edge device?

Reason I ask is, I put a Pertronix digital HP box in my bracket car years ago to fix an ailing digital 6 plus. I chose it based on several factors... shift light output, ground triggered launch rev limit, and 12v burnout rev. limit all as delivered. Works great. So I built a street car, and buy another digital hp box. Well there is two coil out put settings one at 145 mj., the other at 187 mj. So I figure I'll call them to find out why they put 2 outputs on them, the racecar is set at 187mj. I figure running the 187 setting on the street might burn something out. The tech guy says 187mj setting under continuous use could overheat the coil. He says I should run it on 145mj, multispark, falling edge setting for the street car. I have been running the bracket car on the rising edge setting. He says no that is wrong, so we "discuss" this for a while and I respond I will change it to falling edge trigger. Well as I suspected the car won't start. I switch it back and to rising edge and low and behold the car fires instantly, as it always did. But now this has me thinking it has something to do with where the dist is rotated to and maybe I am triggering off an inconsistent signal. Does anyone know what all this rising edge/falling edge stuff really means and how it relates to the trigger signal?