Recently, I received an update regarding the bass horn from the current owner. He's used it, that's the big thing, but better yet, it was recorded on video for some religious service in Europe. 

Anyway, he likes it and finds that it has good intonation, especially just picking it up and playing it without a warm-up.

Here are some photos:

There is video here:
Tim with bass horn and other instruments

I think he's playing it around the 11 minute mark and somewhere about a half hour or so in as well. Sounds great!