The only recommended software is Save Wizard, but you don´t "get" savegames by Save Wizard, you get the saves by websites like this one. The point of the software is to resign other people´s save to your account and, sometimes possible, to switch regions of saves (e.g. US to EU).And yes, you have 3 slots in SW for 3 account IDs, but sharing a license among multiple people is forbidden by SW and NGU.