I have a quilting bar, it attaches to the foot that has a hole in it. I decide what with I want the diagnal grid. I scotch tape it real good to hold it in place. Otherwise it moves on ya!! You do your first qulting and then rest the bar on that quilting and the width is there as you quilt the next row.
Hope I explained this right!!
I'm sure someone else out here has used their quilting bar also!!
Have a wonderful quilty week.
Blessings,
Simple quilter