Any questioning of, or explanation of gain position based on dial position (half way. quarter of the way, etc) indicates a lack of knowledge of the proper way to adjust gains.
For example, is setting the gain in the middle (half way) the same setting on every amplifier? No.
For another example, does pages of people listing their gain position tell us ANYTHING useful? No. We dont know signal strength. We dont know userd defined maximum volume setting on the h/u. And even if we did know.... who cares? There is a proper gain position for your amplifier, given the signal strength etc. In some circumstances the proper gain position might be at 1/4 on the gain knob, or 3/4. So people listing off gain positions is pretty useless info that people could easily misinterpret as useful. Posts like this get people thinking that relative gain knob position (1/4, 1/2, etc) IS the proper way to adjust amplifier gains. This, in essence, turns them into nothing more than volume knobs for noobs. Frankly, Im disappointed its taken till page 3 for anyone to mention this.
There is no such thing as having your gain turned off. Line driver or not.