The mob is dependently gravitated solely on cold hard cash and inducted soldiers or 'made' members are often given a figure that is roughly expected of them to earn by their superiors (acting/official captain) each week/two weeks.
Once the 'made' men have been told what is expected of them they shouldn't ever have to be told again and should independantly go out in the game to earn their weekly take.
Yes. You saw an example of that in "Sopranos": Just after Chris was made, his boss, Paulie, assigned him a "nut" to come up with every week, and threatened to tack on standard vig if he didn't make it. Presumably, everything Chris or any other made guy earned over and above his nut was his. But if he had any sense, he'd kick some of the extra up to his boss to stay on his good side.