Steve Voigt
1. Can someone who wants to use natural oilstones go here and get outfitted? Assume they hollow grind. What is the sharpening sequence?

2. You have your special washita—can something similar be had other than by sorting through many stones with a discerning eye and skill?

Hi Wiley,
If you have a grinder, a tried and true approach is to pair a medium or fine india stone with a hard black or trans ark. Add a bare leather strop and you're set. I did this for years.
I also recommend an Atoma 400 grit diamond plate to resurface stones. A cheaper alternative is 60-80 grit loose SiC on a piece of glass. Very cheap, but coarse and kind of a hassle. I still use this method on my india stone and save the diamond plate for my hard stones.
Things get a little more complicated when you want a tweener stone. The tweener stone is nice because the India is soft and can get bits of wire edge embedded in it, which is a pain. With a tweener, you can skip the India unless you need to raise a really fat wire edge. Dave is right that a vintage Washita is the best choice here. I have a soft ark--I think it's from natural Whetstone--that works just fine. Dave says the soft arks from Dan's are too fine and I trust what he says. But bottom line, a tweener stone is a luxury and not essential--the two stone method will work fine.
At the end of the sharpening sequence, one can also add abrasive stropping to further refine the edge, but it's not essential. I've messed around with a lot of compounds but mostly I keep coming back to my bare strop.
Finding a vintage Washita is not really that hard, unless you're Dave and have insanely high expectations. Watch Dave's video on identifying Washitas and buy a nice looking unbranded stone off ebay. You might strike gold on the first try--I did!
But to repeat my bottom line, start with the two stones that are readily available. You can get fancy and add on from there, but it's not essential. That's really all there is to it.