I still see the dart smoke and velociraptors in S. NV quite a bit. I think the terrain is similar to your canyons, lots of hardpack mixed with gravel and loose rock. You probably have more roots that we have.

I am 6'3" and 225. I run 33-35 back and @40 front. FS bike. I use a Kenda Karma on the front. I like the wider spacing between knobs, I "FEEL" it grips the looser sections better. I'm still playing with ideas for the back. I like the paddle pattern of the Dart/Smoke. There is a guy around here who researches tires and posted that he has a crush on the Swiss Army Avenir. They are interesting. Good centerline for speed and nice spacing for biting the hardpack.