I guess if you are a numbers guy those calculaters would satisfy as a guide,
I would just post a question on RCU,such as I'm flying a ESM Hurricane with a DLE 35ra , what props have you guys tried and which one did you like best?

Then at the flying field you will find, same airplane, same engine, different props as each pilot has different perferences as how he wants the model to fly, how he perceives the model is flying and his skill level to fly that model. cheers - ken