The sewing on the first duffel is proceeding. It has become obvious that there are a few supplies that can't be gotten from the store.
One of them is bias binding made of lightweight nylon fabric. The stores are full of poly or poly-cotton bias tapes. They come in dozens of colors and are really handy for the right project.
Some projects just aren't meant for the matte finish and general all-around heaviness of the prepackaged bindings. Wedding dresses, for one. (Organza bias, not ripstop.) And these pack duffels for another.
The scraps of ripstop that are left from cutting the stow pocket bags are the source of the bias binding for this project. One of their purposes is to finish the seams on the said pocket! Seams that will be on the outside when the duffel is stowed into its little pocket. And while the binding doesn't match the zipper or the main fabric at all, it does match the pocket bag.
The bias binding is also standing in as an interfacing on the main zipper application--just a skosh, as we say, more stability and almost no added weight. (On this project, it is possible that the zippers weigh as much as the rest of the project put together.)