I'm usually around 50-52 I think, though I tend to play really strange session lengths, sometimes as little as 15 minutes, and never more than an hour.

53.03%

48%

68%

I keep my sessions short (between 100-200 hands) I rarely change tables and maintain a 65% winning rate. I also keep track of my winning to losing ratio based on large amounts( over 100% of the buy-in). For me this ratio is also 2:1.

Personally, I think it is important to watch the session win rate along with the BB win rate. If the session rate is high and the BB rate low than it could indicate that a only a minor adjustment in strategy is needed.