I bet super Z6 chains would be the best thing for the front wheels if you want to chain up the front. But I don't see a need as long as you have good tires and 4WD. The only time I would want chains on all four wheels would be if I was driving off road in the snow. I've never had a problem with traction on paved roads as long as I go slow. On dirt roads there's often a small but steep ditch on one or both sides of the road, and it's easy to get one or two wheels stuck in that, and it's hard to get out since it's slippery. I've had some close calls but I've always been able to get unstuck myself.
I own a set of Autotrac chains for the rear now. Walmart also sells them under a slightly different part number for much cheaper. The size I got barely fits my 4th gen stock size tires, but it does fit. I've tested them out at home but never used them in snow.
I've had my share of bad experiences on I70. One year it took 6 hours to get back to the front range from Summit County (it's normally about 2 hours), and most people didn't even make it. I guess the roads were slippery, but it didn't seem too bad in a 4runner (friend's 5th gen with factory tires). We were nearly hit by sliding vehicles 3 separate times, and we passed about 50 cars parked on the side of the highway apparently abandoned. By the time we made it to the Eisenhower tunnel there was no one behind us for a mile, despite 4-5 hours of mostly stopped traffic to get there. Plows couldn't get through (too many people blocking the shoulder), and it was snowing about an inch an hour with a lot of it melting at lower elevations.
Another time I was coming back from Utah a bit west of Vail. We got caught in a whiteout so bad I couldn't see the road at all, so I drove on the rumble strip so I knew I was on the road. Traction wasn't a problem, but the road was completely covered in snow and everything was white. 10 FedEx double trailer trucks flew past me at about 40mph. They had chains, but I don't know how they could see? Maybe sitting higher up with lights low near the road helped? CDOT should have closed the road, but they were nowhere to be seen. The FedEx trucks were presumably trying to make it over Vail Pass before it closed. I stopped and stayed the night in Edwards, and Beaver Creek reported 12 inches of powder the next morning (but I had to go to work). I didn't need chains. I wouldn't have put them on because I didn't pass any chain stations for a while, and it wasn't safe to stop with all the FedEx trucks flying by with no visibility.
The only reason I was on that section of I70 at the time was because I80 was closed due to blowing snow, poor visibility, and several trucks crashing.
After the mess from Dillon to the tunnel a few years ago they seem to close that section of I70 more frequently, at least for short periods. They do a bad job of updating their website with closures. Last year that section was closed for a while, but there was nothing that indicated Loveland Pass was closed. I and basically everyone else drove up to try it. We were forced to turn around above A Basin after crawling in traffic for at least an hour. I should have known better since they have to close Loveland pass frequently for avalanche danger. At least it was a way to kill time while we waited for I70 to reopen.
I think Colorado still doesn't do chain checkpoints like California does (but we should), so even if the code 16 traction law is in effect you can ignore it as long as you don't get stuck or get in an accident. If you do get stuck or get in an accident and didn't use chains they will fine you for sure. You will probably also be found at fault for the accident, and I bet if you need a tow truck they'll charge you a lot more than normal.