The pattern really isn't 'puffy', it's more like a basketweave stitch. I made it with size 13s and 2 strands of worsted as a throw and the pattern comes out nicely. Your yarn is a sport weight not a light worsted, so using the 11s should be fine. It may also take about 4 or 5" to see the pattern, and when it's on the needles that may flatten it out until you get some length to it.
sue- knitting heretic