Here is that video. The back's are opened at around 7:58 and you can see both on screen simultaneously. The Core seems to have a much larger PCB sitting between both pots. The individual mini-toggles are above the Circuit boards which, as I said, could be the biggest difference between these and the many other guitars that offer some 'split' of a Humbucker - either via a Push/Pull pot or toggle switch. Maybe there are different capacitors on the PCB so that in different positions, the signal goes through different Capacitors - one(s) better suited to either the Humbucker or SC positions
Paul did say that the 'breakthrough' came during the development of the 635JM Single Coils for the Silver Sky. What it was though, I don't know but all I know is that these pick-ups are being reviewed very positively. The one thing that I continuously hear with regard to the TCI PU's is how good they work as SC's and how 'convincing' they sound. To me that is also saying that all other 'Split' Humbucker guitars are not as convincing, sound more like a Split Humbucker than what a Single Coil would or should have sounded like.
Anyway enjoy the video. Its a good video too if you are interested in how each guitars sound and compare.