Mike, in place of brass rod for the hinge-pins, perhaps you could use what I think are called leg-levelers, if you can get one small enough.
These are two screw-headed fasteners. One has female threads, one has male threads. If you can find one small enough, that would work.
Beyond that, probably the next best thing would be four microscopic machine screws with nuts. If you fill the slots in and round off the nuts, they'll even look like the factory hinge pins.
Charlie Larkin