I agree about the lack of info regarding stitching placement. Some of them seem "built in", that is, basic cross / diamond. others, I get the impression you can apply them in certain areas. I saw a video of a seam being built in the UV Editor window, but they did not make clear precicely what they were doing to achieve it. If I had to guess, and a guess it is, I think they are applying a line / polygon shape which then forms the stitching. Again, a simple explanation of this process would help enourmously!