Jazzy, I have the variable bass and treble pots installed in my Modulus bass along with a filter and 3-postion Q switch. I really like the bass and treble controls and find them useful for quick tonal changes on the fly. As you may already be aware the variable controls are asymmetric and cut more than they boost but the boost seems plenty robust. The bass control center frequency is 100Hz and the treble 5 kHz. I had the boost and cut switches in my Distillate and, while useful, they are also limiting, either the preset amount of cut/boost is what you are looking for or it isn't. Cutting treble affects bass response and vice versa so it is helpful to have control over both.
Relatively sure that the bass and treble controls come after the filter/Q in the circuit so they can be used for fine tuning. Someone with more technical background can confirm. Hope you can find a simple and efficient solution to your dilemma.