As I said, there are various levels of experience. At a really great restaurant, you get superior food, superior service and really really tidy restrooms. You should tip accordingly. (I still remember the really nice restrooms at Pebble Beach.)

At a "regular" restaurant, you get good service, good food and decent restrooms. Tip the usual 15%.

Again, what happens to the money after it passes from your hands to that of the servers is not your business. It is the server's money to do with what they want. If part of that money goes to the bussers or the cooks, that's none of your business.