Craps dealers either work crew-for-crew or they split with the other dealers somehow. There is no commission.
When you tip you absolutely want to get something for it. That's why tipping at the end does you little good except to get a thank you as you walk away. Tip the first time you get the dice. That way the stick and to a lessor extent the dealers are focused on you. A hard way bet is the best way to go. They prefer that bet and the bet can stay up for quite awhile. Announce that you are off on the come-out roll. That will extend the life of the bet. Never run two bets at the same time. That's a waste of your money. Never make a one-roll bet. Always remember that you are tipping for your benefit, not theirs. Make it work for you. Johnny, Ricky and Sal view you and judge you solely on whether you tip or not. You could be the nicest guy in the world but if you don't take care of them to their satisfaction then in the break room you are a scumbag. Never forget that. They are conning you, much like a stripper does in a club. You want the game to be run fair without any missed bets or pays and you want any borderline calls to go your way if possible. That's why you tip. Tipping because you like them is for suckers. They don't like you. They like your tips so use that to whatever advantage you are able to. If there are others tipping at the table then just wait for your turn to shoot to tip again. The biggest value from a tip comes from the first tip. After that your treatment doesn't get much better so tip early and be noticed. Tipping at the end of your play gains you virtually nothing.
The Fire Bet is also a good dealer bet while you're shooting. It lasts your entire roll and doesn't get knocked down by a losing hard way.