I use sheets for backing all the time and I don't have tension or thread issues. I'm quilting on my Juki TL98Q and sheets are just not a problem. I really think that sheets for backing often get bad reviews and it's been my experience that the "problems" just aren't there. I can buy a decent sheet for $10 and I would be lucky to find fabric at $10 a metre and any back is going to be at least five metres.