I always use the quilt quality fabric- pieced or backing width. My grandmother was a professional seamstress and she told me if I was going to put all this time and work into a project, use the best I could afford. Otherwise, why bother. So, I do fewer projects, use the best stuff, and handquilt almost everything. I also use cotton batting. The polyester beards too much.
Use what will make your project turn out the way you want it.
Cheryl