I try to match the top thread with the bobbin thread. I am not even too fond of a varigated anymore. On Tshirt quilts I usually use a light grey or a tan. You want the tshirts to stand out. If I thought I would see any red on top, I would go with a neutral instead. I agree with Dunster. Sometimes what you think you are seeing is tension issues, when what you are really seeing is a small hole from the needle. If its a needle hole, they will relax ...esp after the 1st washing.