Thinking about it this morning I decided to use the top halves of two Etch-a-Sketch eggs, instead of both halves of one. The two halves are made of different materials: the top is a clear, hard, rigid plastic while the bottom is an opaque, soft, flexible material — similar to what the whole egg for the first capsule is made of. The top is probably easier to crack (in fact, I saw one cracked top among the eggs at the store, probably from dropping onto the hard floor at well under 6.0 m/s) but I’m guessing will better protect an egg; I’m also guessing epoxy will bond better to it, not that the shoulder on the first capsule doesn’t seem to be sticking tight.
Unlike the egg used in the first capsule, on these the shoulder is on the top half, and it’s wider. So the cardboard reinforcing rings both go down inside the extension tube. The egg shoulder is such a good snug fit in the tube one might almost be tempted not to tape everything together for flight… though probably one should.
I then applied CA around the ends of the tube. I did that on the first one, too, but didn’t mention it at the time.