To complete this thread with the outcome:
I wound up buying Nankang (CX-668) 165/80R 15 tires from Discount Tire. I got them for $58 each, mounted and balanced.
They are,in fact, the size tires that were fitted on Volkswagens. They are mounted on Dayton 60-spoke chrome wire wheels. I sealed the leaky spoke with 3M Windshield Weld, the product recommended by Dayton Wheel. Very easy to do and it worked fine. Used a Dremel wire brush to clear the old sealant, Prep Sol to clean the area, then spread the sealant and let it cure for 3 days.
The spare is also a 165/80 15 mounted on a Dayton 48-spoke painted wheel. It has a tube because the tire needs to be stowed with not more than 8-10 lbs of air (and upside down) in order to fit in the storage compartment (the car is a pre-TS60000). Discount Tire is not permitted to mount tubes in tubeless tires, so I took that wheel, tire, and tube to a local tire shop and they mounted it for $10.
The car drives great with the new tires. A lot cheaper than Vredestein Sprints. Thanks for all advice.