100% was the cutoff when I was doing it intraday. The leverage is so high that you have to do it that way.
As I mentioned in this journal, for my current SPY position I wasn’t planning on closing it out if it went below that line, and then when that happened, I didn’t close it out. In fact, my next add position is below the 100% line.
It depends on how you want to size your positions, your account size, your timeframe, etc.