Follow up on this issue. I replaced the tires today. The post above was my only fishtail, but I was spinning the tires regularly from a stop. The streets are wet here in Seattle and I live on top of a giant hill, probably 500 vertical feet of gain over a 1/4 mile. Virtually every time I started up it from that direction I'd spin tires, especially if it was wet. I sometimes turned traction control off just to amuse myself, but it happened to my wife and we have some travel coming up, so I felt like I needed to address it.
Put some new Cooper AT3 4S on today. Light rain and I couldn't get the wheels to spin, even with traction control off. I didn't come up from that same direction, which will be the ultimate test, but it feels like problem solved, plus I have snow rated AT tires on now, which is appropriate for the vehicle and better on forestry roads and mountain passes, which is not daily for me, but not uncommon either.
I would warn people off of those particular Yokohamas, not that I've seen anyone express interest in them. Maybe someone will search for them some day, find this post and save themselves some pain.
Those tires have only the white lettering outline? Or is it possible for blackwall only? The white letter outline bothers me, but the tires seem so good, I may just let that pass.