Seeing the plans, things are simpler than I thought - basically a box firing into a corner, with some outrigging. The compound miter cuts on the mid horn are probably the toughest part.

Have you had a chance to A/B the Deltalite vs the ceramic equivalent? Since weight isn't a concern here, is there a sonic advantage to the neo? In theory, it might have slightly lower distortion, but I'd guess you'd be hard pressed to tell any difference at typical home levels.