Monarch is not mentioned by name in the book, "A Guide to Restringing",
but Hamilton is, on page 125.  When I de-strung a 1929 Monarch I found
the scale to be the same, and ditto with an old Howard.

If you have this book, note how Baldwin used the same scale on both
54-inch and 45-inch pianos.  The Baldwin brand names are Baldwin,
Ellington, Hamilton, Howard, Monarch, St. Regis, H. Schorder, Winton, 
and Modello.

Andy Taylor