1/4" is pretty straightforward. Sew a seam and then measure it across. If it isn't 1/4" it isn't. Sew a narrower seam or wider seam to get the 1/4". Wonder tape is what I used when I started quilting to have 1/4" seams. I put it on the fabric edge. It dissolves in water or you can draw a 1/4" line on the fabric edge.