Dust makes for very slight but quick 'ON-OFF' of the brakes in the drums. Additionally hard linings squeal. Listen to Taxi cabs, they don't want to change pads/linings very often so these are very hard. A parts guy at NAPA may ask you about the service life you want. The opposite are Mercedes Benz, pads are so soft they make no noise. But cost a fortune.
I always ran Mintex in the SCCA race car. A 1959 A-H 100-6 with a 289 V-8 and T-10 trans, and four puck K-H discs up front and two puck K-H discs in the back.
skip.