Joel/AK, I have a good set of 20" wheels but have only run 35"s on them, when I aired them down they looked like Band-Aids, and had almost no side wall, not a good tire for here.
thumbcocker, Narrow tires are like pizza cutters in this dry deep sugar sand, they just don't work very well.
Rio7
Ditch the 20" and run 17", everything will get better, aired up or aired down, ride!