I could never figure out those thread sizes. How big is that in fraction of an inch?
My latest thread I bought was a monofilament fly tying thread that is five mil. I bought both black and white. I find the white is a real bear to use because I literally cannot see it when it is against a light colored background. I have to keep a piece of black cardboard around to hold it behind the area I am working, but that leaves one less hand for the rigging :-(
BTW, this is while I am wearing 2.0 diopter magnifying glasses.