If X is less than the monthly income from your day job (1440), if you are sure your beating the game at $20/hour, and if you are willing to spend the 40 hours a week you were working playing poker in addition to the 30 hours you already spend, you can do it:

If you are 6-tabling with win rate of 8ptbb/100 and a SD of 35ptbb/100, and willing to put in 40 hours a week, X is around 1750. Bump that up to 70 hours a week, and X can be as high as 3700. If you are 12-tabling 40 hours a week with a win rate of 4ptbb/100 and a SD of 40ptbb/100, X is about 900 in the first two months and 1100 thereafter (need to increase your bankroll), and at 70 hours X would be about 2200 in the first month and 2700 after. This assumes 80 hands/hour/table.

To see the numbers for X, just plug the stats into uDevil's calculator and look at the lower 99% confidence interval:

www dot castrovalva dot com/~la/win.htm