I am aware that winsxs is mainly hardlinks thus it does not take up much space.
From what I have read the idea is if you uninstall a program that has a shared .dll or similar these are not deleted from the disk as the link remains in winsxs?
Thus on a fresh install winsxs should be all hard links and only technically begins to take up space when you uninstall/remove something?
Thus the file physically exists on the drive (SSD) and remains even if one link is deleted.
So why not create a symbolic link of the folder to a slower drive; most likely it won't save you any space immediately but over time you will find more of the links become "active" (ie. they are the only link to the physical data) - would this cause a physical transfer of the file from the SSD to the HD, thus saving space?