Steve said
Everyone plays as they want to but I'm not sure how much a spreadsheet can predict in advance.   

Hi Steve. It depends. A good number of things in the game are almost entirely random and therefore way beyond the understanding of a tinkerer like me. I have one function with a 95% prediction value, which is useful for indication only - but even then, it starts to throw in a bizarre result or two. I have a few functions which are over 99.8% accurate and above 99% you can start to rely on it. You certainly can do something very similar using pencil, squared paper - well, a lot of squared paper, ruler and 'line of best fit', if so inclined.

Thanks Michael/Darren. I've got to utilise what skills I have, because I'm trying to play catch up with successful managers like yourselves.