Wow, sounds like adjusting the arc of the shoes is a real dark science. It's not.

Take your drum and put a shoe inside it. If the shoe touches in the middle but not on the ends, put it on a flat surface lining side up and hit it in the middle with a dead blow hammer. Check. Repeat until the shoe contacts the drum all the way. If the shoe touches at the ends but not the middle, turn the shoe so it's vertical, then hit on the end. Check. Repeat as necessary.

It's easier than rebuilding a carburetor, only slightly harder than changing a tire.

R.

http://brakeperformance.com/index.php?ad=google&gclid=CLOSs9nF2rgCFS9dQgodziMAjw