I've noticed that several folks tend to layer their seasonings for the rubs when applying on their meat. In the past, I've just dumped everything in a bowl (salt, pepper, papricka, brown sugar, etc) and slapped it on the butt. Can someone explain the method, reasoning, advantages to layering spices/flavors? Thanks in advance. You guys are really a great and learned group; it's been nice to spy in and pick up pointers.