Quote - re. Genesis size:

I re-saved several modified Genesis characters back to my library and the size of the .crz generated is about 5.6 mb.

A .pzz scene file created with a single Genesis figure was 5.5 mb.

Even uncompressed to a .pz3 a single Genesis figure creates just a 24 mb size file.

 

Have you installed any morphs for genesis? Because that is what increases the size

Of course you haven't because you make your own figures. The rest of the world who uses genesis does install morph packs