So I used some of the scrap connectors that I cut off of the PVC pipe and a little bit of wood to make an 8-way joint for the top of the dome.

I laid it all out nice. Looking good!

But when I tried to put it up, the wood itself could not handle the stress!

So I glued it and screwed it down to a sheet of plywood.

Now, the screws have ripped loose from the wood. Wood is seeming like a terrible idea.

So I used bigger screws this time.

Put it up!

Success! It barely holds itself together!

A few days later:

So, let's get rid of the regular wood and just use the plywood instead...

Seems to be working, momentarily.

Used some string to keep the door from springing out.

Of course, we now have all new types of failure to contend with...

And later:

PVC and wood just don't seem to be cutting it for the parts that need to be at tension. Perhaps I need to make a metal joint of some kind?