Oh that question was directed at me? I thought it was the other person. But yes, I never switch the gain since it's too much effort for me to get a sharp-ish object and slide it. That and even with the Mad Dog, I never had to go past 12 o'clock on the potentiometer, so having the higher gain seems pretty useless for me.
Crossfade off, gain on "0 dB," bass boost off, running on battery.
If I remember correctly the picture you posted showed your preference of potentiometer position below 9 AM where it is not balanced. You must be able to hear a pin drop a mile away. How do the M100's sound without an amp? The review on InnerFidelity said that they are sensitive enough to work on a portable device, so maybe for these an amp is not required.
Edit: At least the amp may not be required for the M100, but other devices maybe they are a good thing.