Here is my favourite way to achieve a scant 1/4 inch on my 15000.
Make sure you have Favourite Stitch in the SET menu turned on.
Use the straight stitch plate. Touch Home and then pick the Quilting menu in the upper right. Select stitch 2. It is a rather “wide” 1/4 inch for most. Adjust by moving the needle to the right to 8.6 or 8.7. You can do that if are using the straight stitch plate.
Now you are going to make this change into a Favourite Stitch that will come up every time you go to this menu. See page 38 – 39 in the Version 1 Manual (might be a page or 2 different in the Version 2 Manual for saving the changed setting to Favourite stitches.