Thanks! I knew about his blade treatments and signatures, not about him directly. He does it for free!
In the missing part he just says the surface has to be perfectly flat or smooth (then goes on to explain the 4mm rubber rule) and yes, the fact that he sometimes receives "rackets" in 10 to 15 pieces, so that he has to put them back together somehow, with the help of a magnifying glass...
A few aborted sentences, which I think is a way to explain that this is very much improvised work, or the opposite of anything standardised.