Vic,
"American Narrow Gauge Railroads" by George W. Hilton has several clear pictures of the Eames muffler in the "Locomotives" chapter - don't have my copy at hand so can't give you a page no. Seems like a lot of them were mounted just ahead of the cab on the engineer's side. I think some were also mounted on top of the cab.
Incidentally re the 2'-0" Forneys, at least one RR, the Monson, ran until 1946 and never used either the Eames or Westinghouse system. They used steam jamb brakes on the locomotive for stopping trains and hand brakes when spotting cars.