So. After examining my inspiration a bit closer, it appears the the "swim dress" had two sashes and a both of silky look texture. Two instead of picking up chiffon, I picked up two kinds of polyester silky-like fabrics.
My question now is, how do I attach it to the dress?
Should I sew the sash to the side seams and then pretty close to the zipper? How do I obtain it without seeing a bunch of sewn-down seams everywhere?