Tim,
It seems like I have made a kazillion blowing horns with an integral mouth piece.
I have also made one with an external screw tip mouthpiece and a couple with internal screw tip mouth pieces. I even made one with a regular bugle mouthpiece.
I haven't tried an applied mouth piece yet, but with your photos, I think I just might give 'er a go. Thanks for the info and inspiration. What do you do, just pressure fit the mouth piece into the horn, or glue it or pin it or?
John