For this top, and for the V neck version, I used 2 of my favourite cotton blend yarns:  Caron Cotton Cakes, and Bernat Softee Baby Cotton.  High are a 60/40 blend of cotton and acrylic, and both are wonderful with which to work.  The Caron Cotton Cakes (4 weight) is a yarn that is exclusive to Michaels stores, and the Bernat Softee Baby Cotton (3 weight) is a yarn exclusive to Joann stores.  Because both are a cotton blend, they wear well, drape well, and wash well -- everything you want from a yarn you use for a garment!

I have written the pattern so that:  a) gauge is not important; b) you can use whatever yarn you like; c) you can use whatever hook you like; and, d) you can make it for ANY size. 

I used 5 of the Caron Cotton Cakes for a size 2X, and 4 of the Bernat Softee Baby Cotton for a size 2X.