Making a moon in stager

Hello, 

I would like to make a moon in Stager. I have downloaded the color and displacement maps from this site: https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=4720

I had successfully made detailed looking moons in Photoshop before they got rid of the 3D features.

Unfortunately, I cannot for the life of me seem to figure out how to:

A) fit the map to a sphere without it looking stretched

B) if I apply a height/displacement/bump map to nearly anything in Stager, it comes out looking clumpy and absurd 

I would greatly appreciate some guidance. Thanks.