I never had an AHA! moment on the Super Alpha build. So, I decided to go with my original plan and build it for 29mm E16/F15 flights. I filled the fins, marked the tube and began building the 29mm mount. I also started sanding and filling the seam on the plastic nose cone. I have never had an Estes cone whose 2 parts were so misaligned-aligned. You know it must have been bad if I resorted to filling. I am not a stickler and typically only lightly sand the joint.
This Alpha will look funky because I couldn't resist using an Estes PVC retainer. Since the cap section is about the same diameter as the BT-60 tube, it will have to protrude below the body's base. To keep the retainer from interfering with the fins, I'll have the grind off ~1/8" of the retainer's raised ridges where it meets the body. I may set the fins back to the bottom root sits at the base of the installed retainer. We'll see.