I completely agree w @Dave the Cook
I also consider rubs to have two , very different components , best treated independently :
1 ) Salt
2 ) herbs and spices .
Aaron Franklin ( Franklin BBQ fame , and Author of BBQ books , PBS series , and MasterClass )
said this about Pork Shoulder : paraphrased : ' it can handle ( a lot of ?? ) Salt '
and his rub had Paprika ( sweet ) . he pointed out it was not used for flavor , but for color.
want to really understand Rubs ?
Take him as your guide.