The reality is, I don't really care about any of it. No one ever divorced because they didn't have uplighting at the ceremony.
Since the silk flowers have some color, you'd be able to see them as a garland in the daylight. Then at night they'll be colorful and festive. We'll wrap the railing of the deck at the reception venue (restaurant? marina?) so that they'll be visible at night. We'll also wrap the railing of the shack, and maybe the posts under the deck. Simple, and cheap.