Would using a volume pedal solve your problem? You could leave the knobs alone and just raise or lower the volume with the pedal. I had the same problem you described and solved it to some extent by using a vol pedal. Once you find the perfect blend you don't want to mess with it. I too like individual controls for each pickup. I like to hear the neck pickup mostly with just a touch or more of the bridge pickup that helps to cut through. I recently switched from MTD dual pick up basses to MTD basses w/ a single MM pup because the pickup is in such a sweet spot for sound and use as a thumbrest and I don't have to worry about the blending issue. Good luck
How could I have never thought of this...
I have never used anyhting on the floor before, alway just plugged straight in...
But this is an option I will try in rehersal tonight.
Still would like to have the control on the bass, but.......