sorry for the delay in response. I just returned from being out of town. Are you referring to using something like an exposed elastic band for the skirts? Usually you want the elastic length to be at least an inch shorter than the waistline measurement, and then when you overlap the ends, it’ll make it even smaller than the actual waistline measurement. This ensures the elastic will stretch to fit the waistline snugly. If you make the elastic band the exact size of the waistline, it tends to feel not tight enough to stay up. Hope this helps.