You normally air down to almost nothing. I was at 8, but have gone down to 6ish before in powder. This was pretty heavy slick snow, that I didn't really feel less air would do much for. As for chains.. I have no idea. I have only used them once, when I had stock tires, and they worked fine, but it wasn't nearly as deep snow as this is. Most of the time, forward movement isn't so much of the problem, as sinking is. Shovel, strap, winch or come along, and most importantly, a friend with another 4x4! You WILL get stuck in deep snow... so a strap and a buddy are the best thing to bring along. I wasn't alone yesterday... I just was blazing the trail and it was so deep I was scared to stop once I was going good so I was ending up really far ahead of everyone, most of the pictures are when I was stopping at flat spots to wait for them to catch up.
Thanks!!