I'm prolly missing something, but what will you achieve by working all this out? If you fly her enough you'll quickly learn the difference between cruise speed and fuel consumption at different power settings, and will therefore know the best way to operate her.
Any numbers you generate after lots of clever theoretical prop-tech and propulsion efficiency research will be somewhat irrelevant won't they?!
I'll put a fiver on 2350rpm being a pretty good "ASI return on fuel expended" in a Grumman with a greedy prop
