Printing Spheres

[curious aardvark]

yeah if you want to be pedantic they're not what programmers call variables. I call them variables because you can vary them and I'm not a programmer and couldn't give a rats arse what the technical term should or shouldn't be:-)
length of neck would probably be 25mm.

You have to embed the neck into the shell to form a solid join. It doesn't actually sit directly on top of the hole. It wouldn't seal if you did that.

Seriously you've never heard of Asterix The Gaul ?
https://en.wikipedia.org/wiki/Asterix_%28character%29