Experiences and recommendations for Snow Chains

I have a '17 Forester XT Touring, so 225 55R18. Just put brand new Vredestein Quatrac 5 All Season tires on it to replace the terrible Dueller H/Ls it came with, because the Quatrac seems to be great in snow and rain and ice for an all season, and I'm in Maryland, where the winters don't really necessitate winter tires, especially not on my current budget.

But I occasionally make trips into WV and other areas that get way more snow and are less likely to be plowed or salted, or at least not often. This weekend is one of those times, and I'm considering getting chains as a backup in case they are needed to get up or down a snowy or icy hill.

I've done a decent amount of research, and have seen that while Subaru doesn't recommend or support any tire chains on new models at all, snow chain companies have made ones that fit in the low clearance wheel wells of stock Subies.

I'm looking at the Konig CB-12, size 104. There's a Security Chain Z6 model that seems to fit too, and a Glacier model as well, but Z6 looks like it isn't as well built, and the Glacier seems to provide less traction.

What I want to know is: does anyone here have experiences, positive or negative to share, and which models?

And what does everyone think about whether just 2 are needed (for a short distance (under 2 miles at most) at low, low speed, and taking care not to spin the wheels, or do we absolutely need them on all 4 wheels to avoid damaging the CVT, differential etc

**TL;DR: Anyone have experiences or recommendations? And can 2 suffice in a pinch, or are 4 absolutely necessary?**