Years ago I played the tipple (Tee-play) in a local Syracuse band, In fact we had two. They are great for Calypso stuff. Dave Guard with the Kingston Trio played one alot. It has the high brittle tone you hear on some of their recordings that might be mistaken for a mandolin. I don't recall how it was tuned exactly except with the four courses of strings fretted like a tenor guitar "C" chords sounded in "F".
I don't play the Tipple any more because of a saw injury but I would if I could. It may be just the "diference" you are searching fore for the elusive sound in a band.