He doesn't use tuning-machines he holds the strings in tune with his teeth. He uses roundwounds because the flatwounds slip through his teeth. Anyway makes for some cool effects.
I thought the strings tuned themselves out of fear... The fretboards respect makes Intonation spot on... The power of Jacks thought ensures the strings produce the sound he wants... And finally... when he says the bass should be Orange, it is made Orange Burst!