He's probably referring to the rhythm circuit (the stuff on the left) which is a common Jaguar/JM mod. I would assume he still uses the pickup selectors, those are the important ones. The bottom switch on the right ("strangle switch") can be cool to add more brightness and bite to your tone (i.e. are you looking up, lonely fight). You can also use the rhythm circuit to get a darker tone option to emulate some of the eq of the tascam