I finished all the fin fillets, internal and external, a few days ago, and they were so strong that they didn't even really need epoxy reinforcement. I then put fillets on both sides of the forward centering ring, then glued on the back ring and filleted it, for 4 strong fins and a bombproof 29mm motor mount.
I didn't like my original design for the ejection tube - I felt it would interfere with loading the parachute - so I took a 29mm-24mm ring and glued it into place at the top of the motor mount. The original ejection tube, with the 18-29mm ring at the bottom, is now free-floating and can be removed for packing the parachute. It'll prolly make a bit more sense with pictures...
Finally, I sanded the fins smooth, tied the shock cord to the nose cone, and glued on two 1" section sof 1/4" launch lug (former the igniter tube for an H165R reload).
Mini Higgs build, part 2
7 hours ago