You have your weights backwards...it's higher number, thinner thread. Perle Cotton comes in 3, 5, 8, 12, and 16...3 is the thickest and 16 is the thinnest. #5 is the same weight as 6 strands of embroidery floss.
And I think Marcia meant to say embroidery floss runs, instead of fades...though it does that too. :lol: