I would ditch the Mallory, because of the cap size, and use the large distributor cap on the stock distributor.
If I had the Jacobs, I would probably run it, but keep a spare OE ignition module in the vehicle. It would probably be best to take an old OEM controller, and use the connectors off of it for the Jacobs. That way, if it gave you problems, it would be no more involved than swapping out a factory controller.
Cummins 4BT/Allison 54/Ford203/Ford205,
Front 89 HP60/Rear 81 GM D70HD
Discs all around/ 12 bolt H1 Rims
Build still very much in progress
78 Levi edition Honcho 360/T18/D20