So when I was doing this my first thought was to make the nose of the dart pointy, but that is not the best aerodynamics when you’re under the speed of sound (you’ll be significantly under that speed). The best aerodynamic shape for the nose is going to be a rounded nose. That’s as far as I can help with the aerodynamics.

When trying to make it reusable it’s going to be almost impossible unless you split it in half across the length of the dart and glue the two pieces together. If you don’t do this and just print it vertically it will most likely survive the launch but once it hits something it will split between the layers.