I did not have a scallop-edged ruler, so I made a template using a pint glass and a piece of paper. I was surprised how important the double-knot tension is. If you don't tighten the knots enough, you don't get the ruffle effect and the scarf lies kind of flat, but if you tighten them too much, the ruffles flair out like butterfly wings, making the scarf awkward to wear. I had to take the knots out of one of the scarves, and reknot it, since the it was so flat. Another point to consider, the scarves lost a lot of length with the knots - they started around 60 inches long, but ended up closer to 48 inches.