Parametric Tubular Fin Jig
In general, tube fins are the easiest thing in the world to assemble, but why not make it even easier? I recommend gluing the first fin tube to the body tube and lay it flat on a table to ensure good alignment. Let the glue set a bit so it's secure, and then glue the rest of the tubes on all willy-nilly and slip the jig on to hold it all in place to dry. Note that you should ensure the jig will slide on easily and hold the tubes securely before you do any gluing. Your printer and slicer may have different tolerances than mine, so size adjustments may be necessary.
This parametric tube fin jig was created to help assemble the Quest Totally Tubular rocket, but everything is parametric so adaptation to rockets like the Estes Super Neon XL or similar rockets should be pretty easy.