Well, it all depends on how disturbed you are by noise..
I have set both fans to be on the regular "quiet" profile, but with a +400rpm higher max. Just make a custom fan profile with the same curve as the quiet one, and ramp up the last step higher to be an "Emergency" if you do get a huge load on the CPU out of nowhere. Bear in mind the fan curves are based on the liquid's temp, so the fan will always compensate late.
Leaving it on either just "quiet" or "Balanced" is just fine, depending how disturbing you find the noise. Just pop in a stress test for 15mins before adjusting them so you know what the max. sounds like on each profile.
Btw, my settings are from the H100i, but it has the same fans.
