Well, it was good I tried it because that wasn't the best fabric for the job. If you look at the photo below, you'll see that the seams are underneath my foot rather than being at the sides of my foot. This is one of the things that happen when you don't have enough stretch. Good to know, right?
I ended up giving the size 42 to my brother because it was too big for me and his feet are just enough larger that the stretch would likely be perfect.
I estimated my dad's size using a men's shoe sizing chart and the existing grading found on the pattern as a guideline. His sock fit well, but is a little too big. I need to take the toe in. Plus, he mentioned that they tend to fall down. So I might consider the elastic with silicon backing as an alternate finish. Though, I would sew it in flat at the exact width of the calf first to see if that's all it needs.
As you can see below, I have 3 of the 4 sizes laid out on the powerstretch. It used surprisingly little fabric. I love that! I still have some left over for... something else.
If you're curious about how these are made, Jalie has a great video on how to sew their pattern. They are such a great company. I highly recommend any of their patterns!
Because I found the comparison between Powerstretch (Left) and Microfleece with one way stretch (Right) rather fascinating, I thought you too would enjoy seeing the difference in how the fabric behaves on the body with Jalie2448 stretch fleece sock pattern.