If you're a professional player which I will define as someone who plays poker as their primary source of income, then you need a much larger starting bankroll. An inadequate bankroll has derailed many gifted poker players, simply because they can't manage their finances during a run of losses. Some of these players become discouraged, give up their professional poker dreams and return to their 9 to 5 jobs. Those who rely solely on poker for a living should have a proven winning record and a bankroll of at least 50 times the buy-in amount for the game you're playing. Achieving a decent hourly income from sit n go games will require playing multiple tables. With playing multiple tables generally comes a lower hourly income because it is harder to get accurate reads on opponents. You simply can't collect as much information for your decision making.
Most players who are making a living playing sit n go poker do so by playing multiple tables. The increased hourly rate from multiple tables offsets the reduced overall return for each individual game.