I spent a day 'studying' with him a couple of years ago. He was totally mind blowing to watch. He played a lot and talked and demonstrated his various techniques, and showed how he uses his various bits of gear.
Hi depth of musicality is totally unnerving, to me anyway. How someone can come up with what he does his just amazing.
On any bass a fretted note will sound different to an open note, fretted A at the 5th fret on the E string for example. He uses this in his compositions, hence his detuning.
He is also one of the most honest, friendliest and down to earth people that I have ever met.
At the end of the day he performed a piece that involved him playing three basses at the same time. This wasn't just a party trick, it was a genuine performance of a piece of music he'd written for three basses.