Picked up a new set of wheels on the internet...where else??? They are KMC Hot Wheels 68 rims covered with Cooper rubber.
Trouble was, the wheels were in Bremen in Germany, almost 900 Kilometers away.
Anyway, I managed to get them here and of course I had to mount the rears immediately! The tires are 275/40-17s, the size and the offset off the rims fit fantastically, they really tuck in nicely under the fenders - suppose I will need some lowering blocks though.
The rims look a lot like the original magnums, only bigger and not steel but alloy... If I figure out a way to color the five triangles between the spokes in flat black, just as they are on the magnums, I will do that.