JiM,
If your present shoes are the "organic" stuff that has been in the parts stores since about 1980 you'll find that old school asbestos works way better. Also, arc grinding the shoes to get full friction contact with the drum is essential.
Some stuffed shirts will huff and puff about how bad asbestos and arc grinding are. Both are harmless unless you work in a brake shop for 40 years and breath in asbestos fibers every day.
If you want any more info on this please let me know.
