FWIW here's where the Xaviere and I are mostly living on the AD50VT these days:
Black 2X12
Gain dimed
Volume dimed
Treble 3:00
Mid dimed
Bass 10:00
I can get a nice range of distortions with my guitar's volume knob, just like the manual says. With the P90s the vibe is generally dirty-but-chimey, good for the sort of low-fi roots punk I'm into these days. This setting also sounds good with a bit of compression when the whim strikes.
I also use this for a clean setting:
Tweed 4x10
Gain 10:00
Volume 3:00
Treble 2:00
Mid 3:00
Bass 12:00
"When I play, I express my feelings very fast." -Yomo Toro