I live and work in rural north-central Montana. This winter I worked as a farm hand and my daily commute was 12 miles of unplowed dirt road with constant blowing and drifting snow conditions. We had a huge winter with a good 3 feet in the prairie. My tracks would be blown in fresh every morning. Temps were typically -15F to -30F so getting there dependably was pretty important.
My work pickup, a 1980 hilux, has lockers front and rear, OME lift and only a set of worn out 32" Nankang Mudstar tires, siped (the Nankangs are barely even 31"). I know I have a lighter rig than an FJ, but I frequently haul anywhere from 700-1,700 lbs in these conditions so I think that makes us even

. I used chains some of the time but when it got really deep I ended up having better success just running 5-7 psi and going for it. I used to think we needed 35" tires or better for deep snow wheeling but this winter has changed my opinion.
Have some decent on board air and get a set of tire deflators. Chains certainly work too but a nice gushy footprint seems to work better for me. Basically the sweet spot for tire pressure in the deep snow is where your contact patch becomes longer than it is wide. Siped tires make a huge difference in forward progress vs. digging down. Worn out mud terrains work notably better than fresh ones. Cheesy side walls tend to work better than nice thick ones.
If you don't want to air down much, skinny, narrow, pizza cutter tires will work WAY better than normal width tires. If you are willing to air down wide is fine. If you don't air down all that sexy width just builds a wall in front of your tire that you have to overcome.
As far as chains go, I like what they call "mud service chains". They have bigger links, less crossovers which seems to be better and they don't break. I have ran a bunch of chains over the years and the ones that are thicker material but less aggressive seem to be the best.