We have the same size head. The temples are the problem. I order stocks when I want them. I have to get large and take the wig in in the back. I have to take in the wig by sewing. I also like to get a custom wigs made.
Many times medium stocks fit well if they have stretch - no sewing needed. But I only do this with wigs in my hair texture. The stock I have now is a medium, but I am leaving my hairline out so the short temples don't matter. Actually, I have worn it glued and it fit well- it has stretch.