The original was a sphere of 100 mm. I have already scale it, now it's a 30 mm space station (not a moon). And the bore for the extruder is aprox. 5.5 mm diameter, fits quite good.
Made to fit in the original MP select mini V2 extruder.
Printed the 3 parts at the same time, took about an hour.
No need for supports, just place everything on their flat side.
Make sure the bottom part fixes right into the extruder shaft. Try to force it to fit, or make the hole a little moldable by heating it.
Once the bottom part fits, glue the trench and then the top.
Good Luck, and may the force be with you!