Don't worry about familiarity--when you put new words to an old melody, it generally is a surprise to people when you tell them what the melody is--even easier when you give it a different feel (like a rock or jazz feel instead of a traditional feel)--

Given that, you are using an Iambic Tetrameter--A couple of the melodies that work with that are "Greensleeves","God Rest You Merry Gentleman", and"The House of the Rising Sun", "Good Bye, Old Paint"-

The reason that Pinetop Slim suggested the Shape Note Hymns is because the book included information on the scansion for the songs--