thx for detailed description. Btw I am not a pro, just an amateur trying to get some reasonable gain staging:) But I have a strong background in electrical engineering, so I understand some of the concepts :)
I decided for myself to gain level my patches against a loudness meter with USB as it is not affected by the big volume knob. I will stay below -3db true peak to be on the save side. I will use your advise to set the volume knob at 12'o clock and set the desired volume ate the FRFR. If the FRFR is not loud enough. I can use the volume know to beef it up.
Hint for Line 6: As long as the output meter doesn't define what it shows (True peak, average LUFS, etc) and has some units attached, it is not really useful. But if the output meter works in the digital space, which I could understand as it would be trivial to be implemented, then an explanation how it is related to the analog domain, would be ver