If you really need discs, Bill, and you want them on a bike you already have, and you're an experienced restorer, surely it's a pretty small project on your scale of things to either have a disc brake tag fitted to the frame and repaint it, or to swap in a disc fork.
I have bike a high-end Gazelle, a first series Toulouse "vakansiefiets" (a bike a Dutchman saves for his holiday...), with a disc brake in the front and one of the older, limper Shimano roller brakes in the rear. Aside from the fact that I hate disc brakes for their tiresome demands for service and expensive pads, and their general lack of gradation (compared to my fave Magura rim hydraulics), that was a very agreeable setup because it distributed the braking effort right even in full on emergency stops. 90% of braking is done by the front wheel anyway, so you don't need a disc in the back.