Problem is, that the higher you raise this percentage, and especially past 15%, the greater risk you have of entering the
Gamblers Ruin Scenario, if you have even the slightest bit of overall system drawdown. Especially in the coming months. In a bull market, it's easy for our systems to pick winners. Historically, 3% has been found by professional traders to be a mathematical safety net for avoiding any such situation. If you raise to around 20%, you run the risk of losing everything.
That being said, I do use 3% as a baseline. I have been known to raise it on occasion, due to trade management techniques; and always according to money management principles. Generally, I do this when trying to capitalize on the Patero Principle. But I would never past 7%.