Goddess Yarns Julia weight?

I want to make the Astrodome hat from Knitty, but I’m not quite sure what weight of yarn to use. The hat in the pic is knit with Goddess Yarns Julia. The gauge on the hat is 16sts/24rows = 4" (the gauge for the matching scarf is 14sts/16rows = 4").

Does anyone know what weight of yarn I should shop for? Thanks a bunch.

Here’s a chart of standard yarn weights (I keep it tacked up on my bulletin board).
http://www.yarnstandards.com/weight.html

From this, Julia would seem to be on the cusp between worsted and chunky weight.

But the Goddess site specifies 5 stitches per inch for Julia.
http://www.goddessyarns.com/
This would put it squarely in the worsted category.

You can check Yarndex for yarns that will give you similar results.