I have the 11000. The center point for my machine is 3.5 and I move it to 4.1 with the 1.4" foot to get a scant 1/4". I think the center point on the 12000 is 4.5. So I would move it over to 5.1 or so to get the scant 1/4". If you are guiding the fabric through at the same point all the time, I don't understand how the seam would not get smaller as you move the needle over to the right? Good luck. Ann