I have no idea of how many sets of rear brake shoes I have fitted in the fifty or more years I have done so but never noted a difference in thickness of lining material until Richard V6 put me right..!!!
As for the OP`s drum coming loose... Perhaps like me whoever fitted the brake drum last had not worked on a wire wheeled car before, and just nipped up the set screws securing the drum thinking the wheel played a part in securing the drum to the hub as it does in a "normal" set-up, and where over-tightened screws ever tend to seize and can create issues when trying to remove them at some later date..?
