While necessarily I've only done this once, and there is a certain RNG element the list of saving throw bonus categories that can be picked from might want to get a look at, or at least the wording adjusted a little. While I was expecting it to be Fort/Ref/Will by the wording, I wound up with +1 Saves vs Disease which was underwhelming on a class that can cast remove disease innately to get when putting a capstone on your current relic.
unless there is some gnarly disease stuff out there i dont know about of course