What are the dimensions of Cathedral Terra? I am trying to model Cathedral Terra from Gurren Lagann in Minecraft, but I need something more than simple artwork to make sure I get it right (with it being a few hundred blocks large and so on).

Is the size of Cathedral Terra (or any kind of blueprint-style image) documented anywhere or is it just "the size of the moon"?
The non-existence of a fact is hard to demonstrate, but I believe this to be the case. I have searched for quite a while and still, the most precise measurement I could find was the mention in Wikia which says:


  The Super Galaxy Gurren Lagann is under half the size of Earth.


It should be possible to calculate a more precise size using the known size of Earth and the visible arc of it in this picture with the relation to Cathedral Terra: