I shaped the pieces on a foam mold as I made them, BJ, so that each one would have the necessary curve. Then I assembled the larger pieces, and made sure the glue had at least 8 hours to set. Actually, the thing that makes this an experiment rather than a completed sphere is that I underestimated how much reinforcement a nine-inch sphere needed as I was building, so this sphere is a bit too flexible. If I hung it, I think it would sag over time. The next one will be completely rigid.
And now that I have that figured out . . . oh, my, more possibilities! I'm thinking of quilled dragon wings . . .