Do you have the any of those white plastic clips (can't remember their technical name) used to hold down your quilt on the belly bar when you float a quilt? If the quilt on the frame is not taking up the entire space, you can make a small sandwich of scraps (make sure the piece is long enough to go from the belly bar to the take-up roller) and scraps of the same batting that you are using in the current quilt; go over to the far left or right side of your mounted quilt, affix the scrap sandwich to the bars and do your test stitching. Just remember to remove it before you go back to your quilt because the first time you roll, those clips will fire off in multiple directions. Clear as mud?