You might want to tweak the values and such- I didn't mess with it that much.
HWs can't have these off the bat, as they're units. They'll also take up 1000kt of space, so unless the planet has that much room you won't be able to build them.
EDIT: Oh, and you'll need to edit the weapons as well; right now nothing can shoot at this since its a different unit type that none of the weapons have in their targeting lists.