Back in the day, we used TORQUE THRUST "D" as they had the rear offset clearance for the disc brake caliper. Todays new American Repo's have no problem, but ask and make sure they fit the caliper.
15x 7 inch wheels will fit, but it is the tire 'width' that rub, especially when entering a driveway with the wheels turned. Many fenders were broken in the old days, that is why you see buyers at swap meets feeling the fender lips.
A 225 x 60 x 15 or comp size tire should have no problem. Best thing, is to go to "TIRE RACK ", or any online service where they show the tire dimensions, and compare it to OE size.
The tire from back in the day that worked with no issues was a 195/75x15 Mitchlin. It was abour 28 inches tall, and 5 inches wide, and they wore like iron, and being an early radial design, had decent handling quality. Zora Duntov did not like the radial, as he respected the tire, but also said it did not 'feel good', and broke away without warning when pushed to the limit.
When Goodyear came out with belted fiberglass tires in late 1968, everyone had to had them. They were about 27 inches tall and 6 inch wide, and rubbed fenders. An E70 X 15 was about the limit, but you had to shave the wheel lips and be extreamly careful entering the drive ways only 'straight' ahead after a wide entry.
In the 80's, 60 series tires came out, and we finally could put one of those on for great performance and handling.
I am only going from memory here, so you have to give the whole equation some thought. As I remember, a 225 x 60 x 15 is only about 23 to 24 inches tall, and changes your ride height considerably, and your RPM at a given true speed. Your road clearance now is two inches closer to the road and speedometer reading will change drastically as well.
The charts today give you the height and width of a complete "tire and wheel assembly " where you can compare 15 , 16, and 17 inch wheels and tire combinations. They all work, but you need to 'read' up on what is best for your applications. This subject may have been addressed here and other forums. The internet has given us great info source at the click of a button.