OK, so a bit of a blast from the past here, but I was doing some research on the circuit design trying to figure out *exactly* what that EQ is doing, and found some info you might find interesting (and a lot that you probably have already figured out):

1.  If you want to turn your TJ into a KT88 Uberschall in terms of voicing, just dime both the master presence and depth.  Those two controls are the only audio-path circuit change between the two amps, and diming both of them is the equivalent to how the power amp is tuned on the regular Uberschall (the Uberschall was originally designed after the Dual Recto -- keep the negative feedback in the power amp to an absolute minimum to preserve harmonic content, and use a funky circuit that feeds the power amp mislabeled as "presence" to control the fizz [and the mud, in the Uberschall's case -- more on that weird knob later]).

2.  The B/M/T knobs are basically a standard Marshall tonestack with one change; the treble capacitor is a different value, which causes the mid-cut that's natural to FMV tonestacks to be shifted higher up and about 3dB deeper.  This is why cutting the treble fattens the low-mids, and it's also why the mids knob acts as a treble knob sometimes.  The main reason this was done is because...

3.  The channel presence knob is one of the weirdest circuits you'll ever see in a tube amp; an LCR circuit that rolls off extreme bass and treble, puts a fairly wide and deep notch at ~400 Hz, and boosts the shit out of everything else.  "Zero" is neutral, and it's really aggressive as you sweep it up; bumping it to just 9 'o clock juices the mid-mids and upper-mids about as much as putting a tube screamer in front of the amp.  The channel volume also interacts with this circuit strangely, so experiment with that some, I prefer keeping channel volume at noon or lower.

The reason why all of this is actually useful to know is that when you get this, you can voice the TJ in an absolutely insane number of ways.  Treat 3:30 on the treble knob as noon, correct the high-end by bringing channel presence to 9:00 or more (or less, if you're boosting it), dial mids and bass around that (less mids than normal, probably a touch more bass), and you basically have the craziest souped-up boosted Marshall, 5150, AND Recto ever, all in one amp, based on the details of how you work the power section controls vs. the channel presence.  Or, you can use it the way Bogner probably intended, keep the treble at a "sane" value, use the channel presence more aggressively to dial in your upper mids, and end up with that really fat yet mean sound.  Either way ends up sounding awesome!