The real thing to understand is - bass/mid/treble comes BEFORE your distortion... those are your booty shapers. The graphic EQ comes AFTER your distortion... those are your money makers.
Something no-one ever really talks about is... the Mark (at least the Mark V and VII, not sure about the earlier ones) can do a LOT of different tones, just be using those pre-EQ controls.
I've made my Mark V sound like a super sludge doom amp, like a Matamp or something, simply by boosting the bass instead of cutting it. There are tons and tons of colours in these amps.
I was in love with my Dual Recto before I got it, but at the moment I only have eyes for my Mark. And if you'd asked me about them even 4 years ago, I would've scoffed and said that they weren't any good for the kind of thing I want. Which would've been a huge mistake!