If using sheets for either backing or on the inside, tying will not be much fun. The thread count is too tight to allow for ease in pulling the needle through, especially if using a thread or yarn that is a bit thick. My mother's Lutheran World Relief quilting group almost always used sheets for backing and frequently used them inside the quilts. The ladies always had sore fingers and hands (even when using pliers) and loved it when regular batting and normal quilting fabric happened to be used.