I am in the process of tying an oversized queen size. I am using cotton crochet thread on this one, but usually use embrodery floss, (all 6 strands) and change colors to match the fabric color. (my quilts are mostly scrappy) That way, you can hardly see the tyes. I used yarn years ago, but don't care so much for it. Haven't tried pearl cotton, but suppose it would be much like the cotton crochet. I just happened to have this on hand, and didn't want to go shopping :) The pattern of the quilt determines how far apart I tie. The one I am doing now is about every 2 inches. Like said in earlier posts, be sure to read instructions on batting package.