I've got a huge wrench set, and used a 1-11/16" wrench(the "open" end). It's a bit sloppy, but did the job without damaging the nut.
It's a bit touchy getting the adjustment just right, as they talked about in that post. First time I adjusted it, the steering wouldn't quite self-center like they said, but the shaking was virtually gone. I backed it off a little, self-centers ok, but some of the shake came back. I need to go about half-way between, and I think it'll be great. I'll do that at next oil change.