You are on the right track making quarter square triangles to sew on either end of your square blocks to make your braid columns. That way the long ends of your triangles will be stable on the long edges of your columns that you will sew together to make the ribbon columns for the quilt. You can make the square that you cut for the quarter square triangles a little oversize by cutting a 10 inch square two times diagonally to give you a little extra wiggle room and trim the triangles after you sew them to the pieced square blocks. Instead of 9.75 use 10 inches. Good luck!