Not sure how I missed this post from the beginning.
If you are recovering from a Source PC crash, first you reinstall the software on the "New" Source. Once reinstalled, go to the Storage PC and open Preferences > Access Rights. At the bottom is a Reassign Sets section. On the Left, choose the old source pc (greyed out at bottom), on the right, choose the new source pc. Hit Reassign, and Save.
To recover from a Storage PC crash, when you are reinstalling on the Storage PC, just choose the same backup set location you had before. The software will claim ownership of the sets within automatically.