Seven-hundred foot tires!
My winter beater MTB has 26" studded tires. I think they are 2.1" wide. They do fine in fresh snow or packed snow, but are simply awful on that semi-packed, rutted snow left by cars before the plot gets there. I like to think that a narrower tire would help cut through, but I can't be certain. In those conditions (loose, semi-packed snow), it seems like studs are irrelevant. Fatbikes skip the studs entirely and go for maximum contact patch and float, but such things are not possible on your average junky MTB frame.
This winter I have my MTB setup as a geared bike, which is a big mistake as compared to last year's single-speed setup. My shift cables and derailleurs end up frozen half the time, leaving me stuck in whatever gear I was in last time the bike was wet. Single-speed was much less prone to frustrate me and less messy too.
In the past I just used one studded tire on the front. It worked just fine. Occasionally the rear wheel will spin out, but that's not a big deal in most situations.