If you were closer I would take those wheels..less tires, off your hands. (assuming they are 15"....they are still 'in' in Oz especially after a quick trip to the polisher)

And you can get studs with all various sized knurling on them of course, perhaps just drill out the drums/hubs to the minimum size to clean up the holes completely round and go from there for sizing? (Speedway sells studs and matching drill bits too from memory)

If they are 1/2" and the threads are still decent, other option would be just screw in studs perhaps as well like used on aftermarket type axles.