Great article. I am currently doing this very upgrade. I noticed a question regarding master cylinders for manual disc brakes. My 1973 Charger had manual disc/drums that worked like a charm, required minimal foot pressure and never caused me any concern during some 36,000 miles of hard driving (I was young). This is a fairly heavy car, too. A quick check of the parts books for that master might prove helpful. Can't wait to complete this upgrade!
Check it out. It may well be the same size as the '67 Bendix, but would be proportioned more heavily toward the front, where the discs are. The Dodge FSM for 1973 probably mentions the model and make of that master cylinder.
I suspect that if you went with anything like the old Budd dual piston calipers, those would HAVE to use a boosted cylinder, but I admit to having seen some stuff for manual disk brakes since I did my job that compels me to admit they may be done so. Mind you, I'm very pleased with the all drum system I currently have. If I ever were to install after-market disc brakes in any conversion, I likely would use Wilwood products.....
I pray your job works out well for you.