I try to use as little cotton thread as possible. That being said, I go for color, and if it happens to be cotton, so be it. The best way to order thread on line is to order a thread card - samples of thread wound and set on a cardboard background. Usually you have to order sepatate cards for every line - cotton, poly, gle in the dark, etc. Some are free, some cost a bit, and some quite a bit, but that guarantees you the perfect color match every time. A friend told me this a while back, and it brought peace and sanity to my on-line shopping for thread.