I've read in the manual where is states to run the front 2 AXE volume knobs full. However, I just don't feel comfortable with that scenario.
A lot of sound engineers claim they run their power amps on full, then adjust using the console. Being a sound engineer myself, I don't follow that rule. I maintain optimum unity gain all the way through the mix, then adjust the power amps for the volume needed for the size of the room.
Since I purchased my AXE, about 2+ weeks ago, I've been experimenting with the volume knobs. I've been running my power amp on 50%, and adjusting the AXE's front volume knobs accordingly. This causes my AXE volume knobs to be around 20 to 25% at rehearsal and 25 to 30% at a venue. With my dual 90 watt amp volume set at 50%, I would never be able to turn the Axe volume knobs to 10. And when the AXE is on 10, my 2:90 is on 2 to 2.5.
I would love to get clarification, as to which way is the best way, or there really isn't any best way.
I do know this for sure: Experimenting the last 2+ weeks with my AXE FX 2 XL+, I fount it is the most forgiving, intelligently laid out processor I have ever owned.