I've fixed most of the original issues with this model overlay, and replaced the placemark with
this , 800kB smaller version...
Changes:
I sorted out the texture darkening problem by removing all references to 'Normals' in the Collada (.dae) file. Worth trying if you don't want GE4 to shade/darken your SketchUp models.

Also, removed the reverse-side colour from the spherical model mesh. This caused flickering and yet more darkening when the clouds were viewed from beneath.
and added a range of options to view the layer at different altitudes. From 4km up to an ultra-unrealistic, but kind of cool looking, IMO, 6350km

....
James.