Substitute Yarn for Filatura di Crosa 501

Hi! I would like to make teh Flowerpower hat from the fall issue of knitty.com It said it was made with Filatura di Crosa 501 yarn (100% superwash Merino wool). There are lots of colors needed (6 in all!) --and I can’t seem to find a resource for this yarn. I did find Swish DK from knitpicks.com --and it seems like it might be a good substitute. I’m rather new to this knitting -and am never sure about substitues. So I was wondering if anyone could tell me a resource for the Filatura di Crosa 501 or a suitable substitute. Thank you so much!
Amy

This should be basically the same as the Filatura di Crosa 501. According to Yarndex that yarn is DK weight and so is this yarn at Knitpicks.
http://www.knitpicks.com/Swish+DK_YD5420168.html