Another way to skin the cat is:
Goto the "Mesh" folder and backup the 5 "SkyboxBackdrop#" mesh files
Make 5 copies of the "SkyboxStars" mesh file
Rename these copies as "SkyboxBackdrop2", "SkyboxBackdrop3", ...., "SkyboxBackdrop6"
Another interesting file to play around w/ is "SkyBoxProperties" in the GameInfo folder. As always backup your original file. Note there are two "SkyBoxProperties" files in this folder, the one you want is 1.92 KB and is a "SkyboxBackdropData" file. Just use notepad to open it...the file seems to define some of the lighting properties (exert below).
dustCloudColor ff3c7da8 - I hate the dust clouds so I changed this to "000000" wtf is ffe7e3d6?
I'm not a fan of variety so I changed the lighting info so that it is the same for each of the skyboxbackdrops.