Grinding the lining to fit the drum will not do any good unless the anchor pins are adjustable so the shoes can be centered.
Years ago newly lined shoes were cam ground at the factory & have a bevel on the ends. They were thicker at the center so the edges don't dig in to the drum.
The shoes are flexible enough that you get full contact with added pedal pressure. The lining soon wore enough to have full contact.
I always put a bevel on the end of each lining to keep the edge from digging into the drum & cause grabbing & pulling.
George
