Could you post the resistor values for the groups that are near the tubes? I'm specifically talking about the ones that are oriented vertically in pairs near each output tube. (Like R6, R7, R8 and R9) I'm really interested to see how hot those might be getting if he's running the current at Menace levels.
Love the off-board mounted pot, led and headphone jack too. And, uh, I'd have to check but I don't think that external PS is up to running the 6528s like Mikhail claims it should be. Unless of course the Hammond trafo is rated to run 25% over its rated capacity.