mast rake measurement

I have just measured my mast rake for the first time using my main halyard as recommended by some. I can't seem to find any literature on whether this measurement is in anyway correct. Our combined crew weight is just over 130kg (286lb). Has anyone got an idea of what I should be aiming for with regards to a measurement of rake?
Thanks for any advise given.
Clint

Start with 13 inches (33cm) and go back as required.
But that's probably different without a comptip.