How many hands are those 15% on full ring?
I would suggest you care more on improving. I Then you will have better edge and you bankroll will grow faster anyway. I know, its boring to study, its more fun to play
I can tell you my story. I wasn't studying much, and playing NL10. Grinded a bankroll for NL20, but at very low winrate, maybe 2bb/100 + rakeback helped make it faster. And guess what happened? I lost much money on NL20. Then found the places where I have to improve. So whats the point even if you hav a bandkrol for higher limit if you are not prepared to play it. Now I will have to grind again to get back to NL20, but now I have a list of things what I have to learn while reaching that limit. Will see what happens. No time currently to study, because I have to study job related things. How to find enough time :/
The problem is I lost much time by grinding at low winrate, which I could invest in studying and be prepared better for next limit. And the better winrate would compenssate the lack of volume. Lets say if you win 6bb instead of 2 bb/100, its 3 times faster, you need 3 times less volume to make the same ammount. And I will still loose much of it and will make only few buks at those low limits. But thats the reality.
Yeah but its easier said than done what I said