This may sound odd but this works great for me. I have a machine foot that is less then 1/4" and more than a scant 1/4" it's about 3/16". I use that for my seams. I have better luck with the pieces being the right size if I sew the seams smaller then 1/4". If I try for the 1/4" it never fails I end up with a block that is smaller then it should be. I seldom have to trim sewing the 3/16" seam. I use a short stitch length to compensate for the smaller seam.