My main folder takes up 17.5 gigs, 3 slaves' take up no more than 70mbs each. Data and Interface folders are the only things I Symlink from main and only take screenshots on main to cut down on space also. After each patch, I copy all files/folders except Data, Interface, WTF, Updates, Background Downloaders, and patch files and copy them over into the slave folders. If you have an addon such as Autoscreenshoter like I do, it will take shots all the freakin time. Achievements, gaining levels, and faction rep changes (You are Neutral/Friendly/Honored, etc..) will trigger this on every toon that has this addon on for, so be wary. My SS folder's pushin 200mbs so far in JPEG files, and I haven't had that addon long. Also, if you're running the PTR, only install it into your main's folder and Symlink the Data/Interface folders to your slaves like the main accounts as well. This will cut down on space also.