Any comment on that stereo speculation? His Rick was of course modded as a stereo so why would he use the same Y-cord with the T-Bird if it wasn't? Has anybody tried it with a T-Bird, each pickup to it's own channel?
I know little about Squire's setup, but I thought I remember reading that he used the stereo feature to run the Ric into both bass and guitar (Marshall stack, IIRC) rigs(?) Maybe he had his other basses similarly equipped.
I've only just recently played with the stereo features on the 4001 and my former Ovation Magnum-I (it was mainly to test the Mag prior to sale). I had built some channel insert cables for my mixer, and the wiring is the same as a stereo bass cable - essentially, one stereo(1/4" TRS) connector wired with the "tip" going to one mono(1/4" TS) cable, and the "ring" going to a second mono(1/4" TS) cable. Each pickup gets sent to its own separate mono cable.
It adds a nice spatial effect to normal playing when the pickups are sent to different positions in the stereo field (sounds awesome thru my F2-B), but I found it most useful for effect processing - sending the neck pickup direct to preserve the fundamental, and running the bridge thru effects, synth, etc... I've actually been thinking about stereo-izing my Ibanez 8-string for this purpose. Not something I'd personally use live, but could be lots of fun for recording.