I have only used Minky for a baby blanket so can't give you any warmth rating feedback. However the raw cut edges shred and fall off in short "tufts" so I would strongly recommend against using it in a rag style quilt. Just use it as a regular quilt backing. I found it very hard to sew with because it is so stretchy and slippery. Use LOTS of pins to hold the edges together when sewing. good luck and welcome to the wonderful world of quilting!!