I often use an overlocker chain thread (see pix Black Wedding Dress - Completion) for stitching purposes. I've used it again for this garment as a type of 'tacking' cord for holding together the 2 petticoat layers of the eldest bridesmaid. To do this, a length of chain (made on the overlocker without any fabric) is produced & using a large eye needle, stitched as if it is an ordinary sewing thread. Taking a few small stitches on one layer, some more stitches are worked on the other layer with approximately a 2"/5cm distance of thread between the layers.
Above left, the skirt is over the dress - right it has the addition of the waistline sash.
PLEASE NOTE: The outfit has not been given a final pressing yet.