Have to use your own judgment--salt can be added, but it can't be taken away! My dear sweet mom taught me that when I first started cooking, lo some 65 or so years ago! Be careful with sugar cause it burns--too much and you'll have more "bark" than you bargained for, IMHO. I basically use Jeff Phillips rub recipe (with some of my own additions and subtractions), because I know his works. Use a few others, too, mostly my own, but learned how much salt and how much sugar, plus everything else, by trail and error. Keep a journal--INCLUDING your rub recipes. You won't regret it. Refer to mine all the time.