I don’t know if it makes sense for your application, really, but @evansd2 has taken flat joins to a new level, recently: Planar butt jointing techniques
@JeremyNielsen did a nice clock with some piecing, too: Clock! – this one might actually be more applicable to your project.
@jbmanning5’s keyhole hangers might come in handy, too: Keyhole Hangers