I started using tracing paper with minimal results. Then I switched to regular printing paper.
Much better. Now I just need to prime. I also switched from using thin CA glue to spray adhesive. I'll run a bead of CA around the edges to seal and fill the edges.
This rocket has what is called 'through the wall' fin mounting. Rather than butt gluing them to the body tube, slots were made from the factory so the root of the fins will go through the tube and get epoxied to the motor tube inside.