Started making a double layer IX quilt for use as a light UQ or as an exterior quilt to my regular down quilt when needed for colder temps. The IX will be covered by 1.1 DWR ripstop fabric (ACU camo), front and back. The problem I have is which material to use in the ripstop channel along the sides and ends for cinching up snug to the WBBB and/or down UQ. I have 1/8-inch shock cord on-hand and same size poly draw cord. Anyone got some experience which might work best?????????