Using Tachs to compare power of a prop on a Specific engine usually has little value other than to compare to previouse readings on the same prop and engine, What is the Ideal prop for one Aircraft is is differant for another, if you going for speed a small high rpm run is needed , TT46 a 10X6 or 10X7 or about is a good choice provided your aircraft is designed to go fast. Slow aircraft that hover alot use flat props for continious static running and load, Sport Flying has a wide range depending on the pilots and aircraft. Even the brand can be better for a size than another for some aircraft. If you want your planes to slow for landing use a flat prop. So far I have not found any prop size or brand that works 100% for every application and aircraft for a .46 size engine. I can't count the number of times people thought something was wrong with thier Aircraft and how it was flying and how the engine was running simply because they had the wrong size and type prop.