For years I have been happy with salt, black pepper, garlic powder and a little cayenne after slathering them with yellow mustard. After 3 hrs at 225 wrap with a couple of oz of apple juice for 2 more hrs. Unwrap for the last hour and brush down with MY sauce that is almost half brown surge by volume.
I like the RT rubs that I have. I have not tried to make any of my own, but I do try several brands. I am almost out of the RT rub kit they sent me. not sure if I will order more from RT, but they have been good.