Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
Take the shoes off the brake plate, then put each one inside the drum to see if there's difference in radius at any particular point around them.Shoes are often shamferred at their ends to fit then in to the drum, if they touch just at the ends then you can file that ramp onto them easily to get them touching along their full length.In other words, you may not need to file the whole brake material, just a "ramp" on the end location of the friction material.