My first and only one so far was made as a trial run to get to know the pattern and figure out what yarn I wanted to make the new grand baby's sweater from. I used Bernat Baby Softee in white. It turned out well. It looks like it will fit a newborn. I think I'll use a worsted for the next one since the baby is coming in April it won't really need a sweater until next fall.
If I do anything differently, I think I will use a different method of M1. Also, the pattern has you making both front sides with buttonholes so you can use it for either boy or girl. I don't like the look of the holes on both sides. When you get to the row (around 110) that has the YO's, if you don't want the holes on both sides, do the following:The first set of YO's are for the left side (boy) and the next set is for the right side (girl). Decide which you want and only follow the pattern for that side and continue in the normal pattern for the other side.
For my Surprise jackets I used Double Knit yarn, which I think is equivalent to the US Sport Weight yarn. The tension for one was 24 stitches per 10cm over stockinette stitch, and it's about newborn size. The tension for the other was 22 stitches per 10cm and it is about right for a 3 - 6 month baby.