[C320-list] Gori prop spec needed

[T. Scott Thompson]

Hi all:  Surprise is a 1999 boat with Yanmar 3GM30F engine and 2.21:1
gearbox ratio.  I need to know if anyone with same engine and gearbox has
successful performance (i.e. is able to reach full RPMs in gear) with a
Gori 2 blade folding prop.  If so, I'd like to know what diameter and
pitch works.  The prop that they sold me (16.5" diameter, 11" pitch) is
over-pitched per sea trial data, and I need to figure out what replacement
blades would work for me.  Gori is proposing a smaller 15" prop but with a
12" pitch.  The latter would seem to be moving in the wrong direction, but
I know that with the smaller diameter this could be the right solution. 
But is it?

Any help will be appreciated.

Scott Thompson