I took the original "Stretch n Sew" classes. They recommended to NOT use the stretch stitch. That stitch goes back and forth and back and forth over the same stitches. It's a bear to take out. They said to use regular straight stitch and give your knit a slight pull as it's feeding thru the foot. I've done that for 36 yrs....and NEVER had a seam come out. I have a serger.....mine doesn't have the 4th needle that gives a seamline..(dumb - 1st ones out)....but I'd think that would work great.