So far so good, the assembly is far simpler without all those screws and now imports properly. I think I might do a quick test adding a huge mass on screws, not attached to anything, to see if they were causing the problem. I don’t want to add them, line them all up and find it doesn’t work. Inventor is great for repeating components though, you can mirror parts and create all kinds of patterns in just a few clicks.
This picture shows the inside of the sphere with a 12mm lens, ie incredibly wide nearly a fish eye.