Although duct tape is the handymans secret weapon, now that it comes in a multitude of different colors, I think one should consider the practical applications in finishing a rocket. First the ease of application, no sanding, no filling, to heck with blemishes and imperfections, they are just going to be covered over anyway. The time consideration, most rockets can be completed in fifteen to twenty minutes, which gives you more time to fly. Another consideration is how it strengthens the structural integrity of the entire rocket. It is hard to zipper through a couple of layers of tape. Fins may become loose, but rarely do they ever separate from the airframe. Of course the different colors available, and I prefer the day-glow colors, making it easier to find. And with the added weight, it does not go as high, therefore, not as far. Boeing paint codes specifications allow a finish as acdeptable as long as the imperfections cannot be seen at six feet, so it should pass the finish test here. Back when I was rafting, after serious incidents, and repairs might need to be made, we were unable to accomplish our tasks without duct tape. With that in mind, if you took a length of duct tape and twisted it tightly, you could probably use it for emergency shock cord. I know I have made impromptu ropes out of duct tape for securing cargo. In all sincerety, I think this is your solution. 🙂
LOL. 😆

Duct tape... gift of the gods.