I would use a 2 1/4 with a 1/4 inch seam if machine sewing it on. From my last quilt experience, I was short on fabric so I did 2 1/4 when I usually do 2 1/2 and it meets evenly front and back. I'm hand tacking but if I were to machine sew it it would hit perfectly. I would test it....only takes a few stitches! Happy quilting!!