Hi Matthew--
Tru-Oil can take a while to fully cure -- maybe a month or so depending on environmental conditions, but it never will be as hard (oops, as tough
) as a nitro or the various poly finishes. A clear pickguard is a viable option. Frank Ford has mentioned, either at Frets.com or on the UMGF that he has a preference for very thin sheets of the "static cling" acetate for clear pick guard material versus the thicker stuff that requires some kind of glue. Worth checking out. I'll see if I can find a link.