How does it sound? FTT has several great sounding circuits, despite the insane marketing verbiage. If I had to guess, I'd assume that Mr. Hayashi has a mid-centered boost in front of a mild overdrive and a secondary volume control tacked to the end of the circuit that's switched at the same time as the OD.
Very interesting... Have any medical friends? Maybe you could x-ray or CAT scan it rather than chisel out the goop!
I'm really happy to hear that you've got your hands on one of these puppies!