To me, every song has its optimal volume setting. I rarely listen above 90dB. OSHA protocols state that risk of hearing loss is minimal with avg 85dB over an 8 hour period. I use hearing protection while vacuum cleaning vinyl and have a decibel meter on my phone. It's amazing how loud everyday activities can be. Riding with the top down in my car is 105 dB! No radio.
On another note @mulveling - are you running the KT-88's in your amps and how much heat do they create. I have the Sig 200's and they are warm here in Florida. I will have to look closer at upgrading the amps as I have the Master Phono pre