I am assuming that you are talking about the little oriyage pouches. Sorry if you aren't ,cos the rest of this will make no sense! I was talking to one of our most experienced Quilter's this evening before I read your post, and she suggested using a softer fabric , rather than pure cotton. She has made these little bags with man made fibre fabrics, with a sheen on them. She said they looked more like the original Japanese. She is a tutor as well as a member of our group. Have a go with some bits of fabric you have around before you buy in the colours you want. Oh, and I have found that one of the rulers I happen to have is an equilateral triangle with sides of 8.5 inches. Maybe you can find one too if you are going to make a lot of these. Sounds good, whatever you are doing.