WASH IT first!!! I have usually used 1/2" seams. It is a little more "stretchy"
If you use a batting with it, it will be quite warm. My daughter LOVES my flannel rag quilt. She loves the weight of it. It has flannel on both sides and warm & natural in the middle. My DH, however, gets way too hot with that quilt and has only used it when he was sick!