Hull rocker shape design

At first I apologize for my bad english.
I am an amateur of simple naval engineering applied to small rc boats (until 3 or 4 feet lenght) mainly sailboats with fin keel and bulb.
I am designing now (for building after) one of that type of boat, a 0.8 meters length and 2 kilograms weight sailboat.
In a general way I know how the design must be, but I have several doubts related to rocker shape. I have seen several small rc sailboat designs and each one place the maximum draft in a different location.
These are my questions: Is there a method to calculate the optimum location of maximum draft (distance from midship toward stem or stern)? What is the influence on sailboat features of that location? What happen if always use midship as maximum draft location?
Thank you very much in advance.
Antonio