Dan's isn't going to be able to tell you a whole lot about washitas. Norton owns the old Pike mine area and has decided that while there is plenty of material still there, it's not profitable to go get it.
Washitas, and I don't know if this is completely accurate, but washitas come out in gigantic amounts and can be cut into stones. Most of the finer arkansas stones, especially translucents but maybe all of them, come out in odd shaped pieces and there is a huge amount waste involved in cutting them to regular shaped stones.
It would be fantastic if Dan's was allowed to take some mine stock from the old pike washita mine, and if you do go to Dan's, you'll be able to see their version of the washita (which is very low density, but is also fragile - the end of mine broke off in shipping, and examining it it's easy to see why, it's a very airy arkansas stone). But at this point, the mine is closed and none comes to market.
I have been an ardent stone purchaser, and I've sold off most of what I tried and kept a fair amount (that in itself is a total waste of money, the cost of ebay, shipping, etc, takes a 20% slice or so of everything that I try), and I think what you want to look at at dans is stones on the harder side, the softs are better gotten somewhere else. Dans' black stones and trans stones are as good as any I've ever seen, though, vintage or not. They are better than both versions of nortons (and I have bought several trans and a black from norton), but the softs from natural whetstone have been better (to me) for a stone that you want to have cutting aggressively (and NW's prices are very low, which is a double bonus).
Pike mine washitas have no equivalent elsewhere, though, and Dan himself will tell you that they're not the same thing (Dan's washitas vs. pike). You'll be getting arkansas stones from Dan's, which is fine, they are fine people and they will not mislead you.