The softer the pad is, the more difficult it is to sand without tearing. I freeze softies and use auto tranny fluid as grinding lube. I like the harder pads for the way they finish.
Spend the time up front to get the stock and pad as flat as possible so the interface is perfect. Most of the pads I get are not flat and need work. PITA.
Use a grinding jig for the angles, they help get you to 98% quickly. They come with pretty good directions. Brownells/Midway.
The freaking rubber dust is awful. If you don't have a serious dust control vacuum system (I don't) get dust masks.
