I'm not sure if this has been done yet and don't want to take credit for something I haven't researched fully, I just want to share an idea I was fooling around with.
I wanted to hear both the -2 and -1 octaves together using a blend of some sort. initially I was worried about buffering signals and frequency cancelations but just grabbed the old iron and went for it. I desoldered the octave switch and replaced it with a (after experimentation) 1k linear potentiometer.
octave switch 1 to lug 1 of pot
octave switch 3 to lug 3 of pot
octave switch 2 to lug 2 of pot
simple as that, just replace the switch with a 1k linear pot wired up the same way.
there is a small drop in volume at mid point in the rotation but not bad at all, worth it to hear them both mixed together.
maybe there's a better way of doing this, would love to hear from anyone who has more experience. Enjoy.
It's also possible just to put volume pots from the output of each octave, and a third from the straight fuzz with resistors from the outputs of those pots to the output to give an individual level control for each voice