nl bankroll & ev question

[Jadaki 1]

I've built a bankroll over the last few months online, and am looking at taking that and stepping into the cardroom at my local casino a little more regularly now they they have expanded to include a regular no limit game. They usually seat two no limit games, a 1/2 and a 2/5. The buy in for the 1/2 is 100 and 2/5 is 200, no more/no less for either table. In the few times I have played the 1/2 game, I am up a little more than 300 dollars in roughly 14 hours of play over 4 sessions.My question{s) is what type of bankroll would be good to ensure my ability to stay at this limit, and what should I have before moving up to the 2/5 game. And while I am familiar with EV for limit games, I'm not so much clear on the subject when it comes to NL. Can somone clarify what my EV should be for this type of game?Thanks in advance...

[CobaltBlue 662]

NL estimates range anywhere from 10 to 25 max buy-ins.And when you say EV, you mean earn rate, right? Cause EV doesn't really make sense in that context.