During winter, jackets are an everyday companion. They are large and very laborious creations, which can sometimes drive me mad, but in the end I think it is all worth it.
I work with several different grades of merino wool, from the coarser to the thinner and softer and adapt the mixture to the targeted season. Merino wool can be really fine and soft. The superfine that I use is 18 microns thick, far less than a human hair. The finer it is, the more expensive, of course. I have never experimented with cashmere or angora fibres but I believe superfine merino can stand up to them.
My jackets are generally fastened with a pin, which makes them more versatile and broadens the range of body sizes and shapes they will fit.