I raise Volume Knob 2 (bright Volume) to just over the loudness I want.
Set the tone knob at about 90%
Then raise the un-used channel volume to around 80% +/- to keep it just on the edge of a nice blues breakup.
So on a Richter 5E3, with A Strat,
Guitar in Jack 4
Volume 2 set at 3
Volume 1 set at 8
Tone set at 9
If I want to get more grit, I lower volume 1, If I want vicious overdrive, Dime Volume 2 and stand back!