Used 33/36 for most of my miles but when loaded and on the hwy, I would inflate to 35/40. Never really needed to air down for the usual forest service roads I ride or for sand. If there was miles and miles of sand ahead, lowering pressure would be a good ideal.
Hmm, maybe I'll try a little more pressure in mine. I've been worried about the 33psi max stated on their website, but if people are running 40's with no problem, maybe i'm too low. Yes, the sidewalls are VERY soft.