If you want to attach the drums to the hubs to keep them from slipping off during a tire change, just tap the rivet holes with a thread, and use a flathead machine screw countersunk even with the surface of the drum to hold it on.
If you do it this way, make sure you use anti-seize compound on the threads. The brake drums see the harshest environment which will rust those screws in solid. I would also use a higher grade torx head so it would have some beef when trying to remove them. You may want to use stainless.
Whatever you do, don’t use a slotted flathead machine screw. That will decrease you chance of removal.
