M.I.Late

I am doing a silhouette of a couple under an arch. (It measures 3 feet x 5 feet and will be used as banners in a wedding.) The background is white, I have a light taupe and a darker taupe. The arch is not really correctly proportioned to the couple. It's ok - it just looks closer to you than they are. The arch is the frame in that it also frames along the bottom of the banner. My question is this: Do I want to use the darker fabric for the couple to bring them forward and the lighter for the arch to make it appear farther back or do I use the lighter fabric for the couple to bring them forward and the darker for the arch to make it appear farther back? Help! I need to cut the appliques out tonight.