Phil Jamison has a great question in the MMD 980525.  I have
found over years of tuning fair organs, etc., that the builders often
"built-up" sound by adding one pipe in a mixture which was tuned a
forth (or fifth) higher than the note being played.  As an example, a
47-key fair organ by the famous firm of Wilhelm Bruder used a mixture
of 5 pipes for each note in the 19-note melody section.  The lowest
note being C is made up of pipes playing  C2, C3, C3, "G3", C4.  The
G3 is sounding a forth higher, or 2 2/3.

If two notes at an interval of a fifth are played together (C & G)
a note one octave below the lower note will be heard.  Many people feel
this combination of two notes played a fifth apart produce a better
sound than one pipe playing the octave below, and in fairground and
street organs the [case] size is always critical.  I know this doesn't
exactly answer your question, Phil, and is really only intended to help
you and your ear to make the final decision.

Best Regards to everyone

Ron Schmuck
The Great Canadian Nickelodeon Co.
http://members.aol.com/tgcnc/