I piece and paper piece at 1.5 for secure stitching, that's what I was told was the best to insure your seams don't pull apart when I first started. I never see any stitching when I press open the seams. If I am a little unsure of matched seams I first stitch at around 3.0 on a couple of short spots so I can turn and see if I am matched then secure stitch the entire length. The 3.0 is so easy to remove if I am off and have to reposition.