One slight correction about Nelson-Wiggen xylophones.  In the
Nelson-Wiggen coin pianos I have seen, some had a marimba [xylophone]
with 20 notes in the 5X, and some had 28 notes, but never 22 notes.
All the 4X models seem to have 28 notes, with xylophones made by
different companies -- not all are Deagan.

Don Teach - "Home of the Nelson Wiggen color decal"
Shreveport, Louisiana