Hi,
Sorry for the late reply!
You only need to edit the BIN files. Actually, I think the XML files are redundant leftovers that I seem to have forgotten to clean out before uploading the package.
The easiest way I think would be to first create renamed copies of the four Time of Day BPs (GN-RW3-Autumn.bin etc.)
Then edit these to your liking, edit the RoueProperties.xml to link to your copies of these files.
Also: editing all the color values might be a lot easier in the Blueprint Editor, where you can use these handy sliders to set the colors.
Exporting only works well, however, when you have the source files of the sky dome too. I'd be happy to email you these (and anybody else who wants them) -- just let me know. Alternatively, you could also leave out all the sky dome, sun, moon etc. references in the BP editor, in other words export only the color settings, end then paste in the skydome etc. lines from my original Time of Day BPs.
Cheers,
Michael