So does that mean that you run your amps with the gain turned all the way up but you keep the volume down on the head unit?
My interpretation of what he sadi is that he's willing to accept the lower efficiency of having the gain low.

Keeping the gain at max and HU volume low is asking for noise. Any noise introduced after the HU is amplified more the higher the gain is set. This concept is the reason for line-drivers, which increase the voltage "early" in the signal chain and allows you to keep the gain on the amp lower, thus amplifying any picked up noise less.

/Michael