Still using PDW, but have the 29er crud on my Flash. PDWs are huge but clip on with press studs. I find I catch the rear a lot getting on and off the bike which un clips it. 29er crud rear is nice and long and I think would work well on the fat bike. Not as wide but most muck is thrown up off the centre line so it doesn't really matter.
I'll bring the PDW so you can have a look and try them on.