i've always felt it's your quilt, do what you want. I started quilting before there were a lot of quilting fabrics available. for some reason, quilting fabrics weren't so widely available in the 70's when i was a teen and got heavily into quilting. before that, i used my grandma's scraps. Polyester blends tend to pill sometimes. i have used gingham in almost all my quilts in the early days. i've heard some people's horror stories about poly blends. also, that the poly cut thru cotton. Never had a problem with that. Polys hold a stain better also. In the 70's they had A LOT of calicos. As I've said, it's your quilt, have fun with it.