Hi,
interesting topic!
I personnaly can not understand how Kevin can spin that fast with these tires. After switching from 1,85" tires to the KHE Mac 1 which are arount 1,6", it took me some time to get used to it. But after a while I liked the advantage of them that everything where the tire is rotated on the ground (getting into a mc circle, steamrollers and so on) feels so much easier. After some years I tried a friend's bike with 1,85" Frequency Gs and it felt super slow!
Some of the guys I met at the KTGM jam in Budapest last weekend told me that they like a little wider tires because it is more stable for rolling tricks (straight line rolling tricks). But they pump them up to 10 bar or more to compensate the highter resistance. Not all tires can handle this pressure.
So I think it depends on your preference but also on the kind of tricks you are doing.