Just an FYI , Regular quilters cotton is only 160 thread count. In using sheets for backing to not go for the higher thread counts. One of the reasons is the needle size used will leave a hole in the high thread count sheets. A top stitch needle will leave holes ... so if any stitches have to come out and be re-done .. you will be able to tell where the old stitch line was.
I use sheets with under 200 thread count.