I asked Mike Crupe of MAC Performance to make up a kit for me to my design, using his 54mm canvas phenolic tubing.  This is near-scale model of Patriot Advanced Capability - 3 anti-missile missile.  It uses a 29 mm mount, and is (theoretically) more stable than the small fins make it look, thanks in part to the foamed nose cone that contains a payload bay.  Hopefully, it'll prove itself in the air...