I don't have any expectation to find any hones that are finer than my black ark. But I think it'd be super cool to have a few rough cut stones, like the ones in the video you posted, for sharpening knives and such.
I already learned things from the video you posted. It seemed kind of nasty to use spit on a hone, but I decided to try it on a pocket sized hard ark from Dan's with my Case Trapper. Spittle definitely worked better than water! Dare I say, I think it even produced a finer edge than Dan's honing oil. I'm tempted to try it on my black ark with a razor.
I use spit on my axe and machete stones and on knifes in the outdoors when water is not around or if using an Ark. Works great, but kinda nasty too.