I would use the the Basssman 70 layout with the TMB control on the Normal channel from the Bassman 10 schematic. I would also use a 10K pot on the Bass channel instead of the 8K2 resistor. But that's your call as to what you prefer. If you were to not use the mid pots. You could replace them with 250K pots to use as gain controls for the third gain stages. FWIW, the tone stack on the Normal channel of the Bassman 70 schematic is a copy of the CP103 tone stack as found in "The Who" amp.