Greyscale seems perfect really. Just imported the Howling Fjord and it looks superb. The graininess was no problem at all really, since the importer for Skyrim already loses much of the image quality anyways. I'm going to be painting the terrain I now have as well as placing a few mountain scenes in and I'll post some pics here for you when I'm done .
Thanks again, and I will be sure to credit you on the team that will eventually finish this.