Do tell...I'm very interested in hearing about your Knuckle!
Congratulations on the beautiful Quake.
OK, here's the deal with the stereo setup... It has a single TRS (tip-ring-sleeve) jack that can take either TRS cable for stereo operation or a regular cable for mono. There's a five position rotary switch that sends each pickup to either the tip or the ring or to nowhere (off). You can think of the tip and ring as left and right... So in mono mode, you can get neck, bridge or neck plus bridge, or mute as options -- and then in stereo mode you can also flip-flop neck and bridge between the two outputs if you want.
The point of this, which is not obvious if you've never played a stereo bass, is that the two pickups are slightly out of phase (visualize how the vibrations propagate up and down the string past the two pickup locations...) and this slight out of phase effect, even more so than the tonal differences between the pickups, creates a sense of "space" when you run a reasonably symmetrical pair of amps -- or for recording, when you pan each signal towards opposite speakers in your stereo mix. It sounds particularly dramatic when you play chords, but it's still quite apparently on single note lines too. I wish I had a home recording setup so I could post an example, but unfortunately I'm a little behind on learning that technology. Hopefully my band will do a recording in a few months so I can post something.
I just noticed the Link Removed has some new content. There are now 3 designs to choose from.