If you're averaging a 50% ROI at $5.50, that's an incredible number. And looking you up on SharkScope
, I have my doubts about the authenticity of your claims. Unless you've found some incredibly weak people in private tournaments.
If your claims are accurate, moving up should be based on what you can afford to lose, which is a bankroll thing. If you want to cash out rather than keep a cushion online, then move up but move down *quickly* if you start to lose is always an option. Just make sure you're willing to move down and don't get stubborn and break yourself at the higher limit with higher competition.
If you play for twice the buy-in, you'll only need half that return to stay even with where you are now. But if you're crushing the games at this level, then you should probably multi-table and maximize your profit from the easy pickings at your current level.