Set your gains so that it sounds balanced playing music, use your VOLUME KNOB and common sense to not break things when you are playing material that pushes things beyond their limits.
The issue being you may well need all the gain you have for certain songs but other songs will break things at the same volume level. Knowing the limits of your equipment and discovering which frequencies are easy on things and that are really stressful for the system is something that will require you to do some experimenting.
The great thing about how humans perceive sound intensity is that once you've hit the limit of your equipment you can back off 3dB which isn't very dramatic and be running everything at half power. Back off 1db which is just the threshold of noticeable and you're still well within safe operating range.
That all being said, if you're making your amp go protect often there may well be some other issue that should be addressed. Inadequate current or running it below it's minimum stable impedance are most likely issues.