I brought home some of our partially finished layette pieces two weeks ago. The seven gowns needed neckbands and the 3 receiving blankets needed the serger edging. When I take them tomorrow to sewing circle, the ribbon will be run through the neckband and tied in a bow. I'm including the pattern in this post for the people who have slow internet service. I included the link yesterday but it takes too long for the link to open with slow service.
I don't measure the ribbing. I just stretch it slightly as I sew it on and cut it off when I get to the end. We used to turn in the edges of the ribbing at the front but after all kinds of problems sewing it that way we decided to just use the raw edge. It won't ravel and these gowns are used for such a short time since babies grow fast. Click on the photos to enlarge them.