I use 1/8" industrial grade rubber, a fraction wider than the jaws, and just a single piece laid in there like a saddle, or U shape. In and out in a second, holds tight, doesn't leave a mark, takes a ton of abuse, lasts for years. I use it from the time the stave is roughed in until the finish is on, leather on the grip, string serving and silencers, any and all odd jobs, the works. I think in all the years I've been doing this... I'm maybe on my third little piece.