Hi Bussie,
I was concerned about data file placement and space allocation in WB6 too because I always set up machines with a 10 to 15 GB C partition for the OS and applications. Why? Because WinXP runs better with less work for the HDD reading a whole disk when all the OS and Apps are on a smaller partition. D partition is used for data files like my documents, etc. This is also a good method when having to do rebuilds because you don't have to wipe the whole disk, only the C partition, to reinstall a fresh copy of XP.
Anyhow, with WB6, some of the data files for this application are stored in
C:\Documents and Settings\All Users\Documents\Stardock\...WindowBlinds, IconPackager, SoundPackager, and ThemeManager.
If you download a lot of WB skins, make a lot of Themes, and download a lot of IconPackages; the C partition fills up quick.
Also taking up a huge amount of disk space are:
C:\Program Files\CursorXP\Themes
C:\Program Files\WinCustomize\LogonStudio
C:\Program Files\Stardock\Object Desktop\IconPackager\Themes
...and so on for other SD apps.
As this is the case and since I like using these products, I used Acronis Disk Director 10 to increase the size of my C partiton. Acronis can do this without wiping the drive unlike Windows computer management, disk management tool which wipes everything if you want to resize a partition.
Hope this helps.
Cheers, f