The yarn I used is DK cotton mercerized yarn from elann.com called Sonata. It's about 2 strands of the doily thread. DK is slightly smaller than worsted weight (the big yarn) and slightly bigger than sport weight (the med. sized yarn).
I recommend this thickness of yarn because it works fast but it's not too bulky so the drape of the fabric is good.
Thank you! It's a top down pattern that I just made up as I went and I made a mistake in calculating the increases as it went down so it was too "skimpy" so I made the edging and it turned out so much better than I ever envisioned!