Bro.. listen to you music. You can hear clipping as low as 2%between 1k and 4k.
SUBs are harder. It's closer to around 5% but once you hear it back off Abit you perfectly fine.
TBH, I'm pretty paranoid and salty atm about setting gains. I just had a $150 Beyma blow on me. I set my gains by ear, I had clipping for just a moment and turned it down. A little later, my speaker sounds like a queef machine.
I'm sure that setting gains by ear works often but I really don't want to take a chance of burning more $.