I finally assembled the baby sweater knitted from Katia's Jamaica yarn. It turned out really well:
Yarn: Katia Jamaica Color # 4010
Pattern: Moss Stitch Sweater from Debbie Bliss Noro Collection 2
Knitted on size 5 needles, with size 3 for ribbing.
I basically picked this pattern because it was the shape and pattern I wanted. I imagined a moss stitch sweater the moment I saw the yarn. I have no idea about baby sweater sizing so I needed to find a baby sweater to get the size right. Then I just had to knit the gauge swatch, plug in the dimensions and knit accordingly.
Now, I have ideas for several more sweaters so I had better get knitting.