I do not think you would ever normally machine the carrier drums thin enough to be of concern. Bear in mind we are dealing with mechanical brakes that apply much less pressure than modern hydraulic, power systems and very sturdy drums. Many cars in the 20s had stamped steel drums about 1/8" thick. Another point to be made concerns grooves sometimes worn by rivets protruding from worn linings; a bit of a radial groove will have virtually no effect on braking & is sometimes more desirable than turning a great deal of metal off to remove the groove.
Most reliners can apply thicker lining & machine the newly lined shoes to the exact diameter of your finished drum. Each side does not need to be the same diameter but be sure not to mix the shoes up!
From personal experience I have found that bonded linings often come loose on vehicles that are used infrequently. I always prefer to have riveted linings if at all possible.
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