Time Machine with Sandbox
 

I've decided that in order to save space on my Time Machine backup (and thus to keep older copies as long as possible), I'm going to do the following:

1. Partition my main drive into two volumes, "Macintosh HD" and "Sandbox", and use SD! to create the Sandbox volume.
2. Have a second drive (internal, in my Mac Pro), "Macintosh HD BU", which will be a complete clone of the "Macintosh HD" drive, using SD!, on some kind of schedule.
3. Have a third drive "TM", used for Time Machine backups.

My question is this....I want the Time Machine only to be backing up my Documents folder, without any system files and stuff. (I don't need to backup the system files and applications, etc. because of the existence of "Machintosh HD BU"). On the Sandbox volume there are lots of files, including bunches of symlinks to stuff on Macintosh HD. Am I safe simply to add "Sandbox" to the list of items to exclude in TM? After all, everything I want to have backed up by TM is on "Macintosh HD"

Yes, that should work.