Dude, tons of people have nailed his tone, just look on youtube, lol. and it's always a Randall RG or Century head, go figure. There's no conspiracy about his tone, so quit it with your nonsense. In the studio there's these things called Equalizers, it's amazing what one can do with a equalizer. There's also speakers, microphones etc... many ways to shape the tone. It's no ADA mp1, go find one picture of Dimebag with a ADA mp1, go ahead... and that Marshall you saw was probably some other bands equipment. Dime kept his rack rig in the back hidden from the audience. I have no doubt Dime used some tube amps to add flavour to his tone, but the core of it is Randall RG100ES and Century 200.