I reckon the spreadsheet could be an ad for a low carb diet. Jim could just as easily presented the data as type in what gear you have and see how much weight you got to aim for to get it working properly. It explains exactly why a 5.8 no longer works for me in 20 knots but works in 26.
I don't understand the fin stuff too well. Not sure what he means by "heavy footed". Anyone got a good link to a site that explains all about fins?