The single most useful piece of advice I can give you is bring an MXR 10-band EQ for the effects loop of the Powerball
Cut 500Hz a tad, boost 1KHz 2KHz and 4KHz a little to bring the mids to life, and cut 8KHZ and 16KHZ quite a bit. Now you can use the presence on the amp without sounding harsh and the mids will cut through like a chainsaw. IIRC I had 16KHz almost all the way down and all harshness was gone! Turning the presence up after cutting these frequencies really brought the amp to life.