The nose cone tip and base were both drilled and tapped for 3/8" threaded rod into their dowel cores. Here's the jig that Evan and I made to align the parts when the epoxy cured. After a bit of head-scratching, I lined up a long straightedge parallel with the lower tube, offset to clear the bulge in the cone and the clamps. Parallelism was checked with a level. Then I measured down to the centerline of the tube, adjusting a plate which had been drilled for the front tip stud. This was done for both axes. It took some perspicacity, I humbly submit, and worked nicely.
The "flying buttress" external support ribs need to be structural, due to the relatively weak internal structure. I cut them from 1/8" CE garolite (cotton/phenolic) and epoxied them on. Later, I added fillets using my favorite epoxy putty, Quickfair from System Three.
The paint booth. This is before the wind kicked up. Everything was blown over, and almost all the ribs snapped. I suppose it's fair to conclude that the internal structure isn't strong enough!