May I suggest a couple of resources. I used an Excel spreadsheet that I downloaded from the EAA web site. At the time, I was looking at props for a Jab. Neal Willford wrote it for S.A. in 2004. Search for "propeller spreadsheet" on the home page.

Ed Sterba makes props down in FL. and his web page has some good info and rules of thumb. He has a link off the Great plains web site.