I pretty much do o.k. with my seam allowances matching. I'm assuming they are a scant 1/4", but whether they are or not, they are all the same size and that works for me. I've heard that if you stick a hunk of a Post-It Notes pad to your machine exactly where you want your seam allowance width to be, i.e. a 1/4" from the needle, your fabric butts up against the pad and maintains the width. You would need about a 1/2 of a pad of Post-It Notes (sticky side toward the needle), enough to where it's thick enough to keep the fabric in line. I have not tried it and am aware that it might even get in the way of the presser foot. I have used painter's tape for really wide allowances (as in home decorating), but had to be very careful not to let the fabric stray beyond the edge of the tape, so I think the Post-It Note pad idea would work better than the tape.