Being cheap, I shop a lot at Sierra Trading Post. Because of the shipping costs it is best to order several different models and sizes at once. Then try them out indoors and keep whichever one fits best. Send the rest back and possibly order spares of the one you like. (I paid a total of $130 for three pair of Montrail Continental Divides last summer including shipping. I tried four different models and sizes before settling on them, then ordered two spare pair)
>(I'm also struggling with making the leap out of Smartwools and into Injinji socks full time. The problem is that I've never had a pair of Injinji wools take the abuse of Smartwools. And they cost a ton!)
Last summer I took my longest trip ever (220 miles), first with trail runners instead of boots, and first in several years. I bought a pair of wool Injinjis "just in case". Starting day two I wore them for the rest of the trip and I'm sold- both on toe socks and on wool base layers. I used Smartwool socks over the toe socks and basically wore out two pair.
I'm thinking that a good combination would be the wool Injinjis inner socks, with a tough, dense weave synthetic outer sock. This should help protect the delicate wool, keep all but the smallest dust particles away from the foot, and help to reduce friction.