Try rolling your bass and treble to 7. I keep my mid around 5. Just enough to help shape it. Do the same with the gain when you have it in crunch mod. Bring the delay down to 2 and run the fx on chorus. See if that gives you a fatter sound.
OK. Like I said. I will look deeper into this amp and see what I can get for ya. Give me some time. I dont have this amp so I just work it out in my head.