I use sheets all of the time and I can't imagine why you would rip off the header and waste valuable material. The hems are usually stitched with a chain stitch and rip out very quickly. Even if they are just straight stitched a few minutes with a stitch ripper over a cup of tea and they are out and will give you additional inches for your back. Sheets work really well for machine quilting or tying. My quilt guild uses them all the time for the backs of our large Community quilts as they can be purchased for less than $10 Canadian (the last ones I got were on sale for $5).