I'm not sure the people wearing 2 pairs of wool socks are wearing HEAVY wool socks. Even so, if you buy shoes that are larger than normal, extra socks will help while they feel too big and then when your feet swell (or you realize your normal shoe size really was too small after all, just like everybody tried to tell you) you can take off a layer of socks.
In my case, I ended up wearing shoes 2-4 sizes too big (Men's size 8 to 10, I think I'm a size 6 by length alone) and that worked out best for me. To reduce having my feet slip around, I buy foam insoles, where the top layer is foam. This provides enough friction to keep my feet from sliding around. I also wear the thinnest wool socks I can find, or the next size thicker, and only one pair.
Also, in So Cal the humidity is very low. It's a dry heat. You can air out your feet and socks and have them dry in a few minutes.