Everything changes with a new hull. Taking dimensions from another boat will give you a start for trial and error. All three components of lateral resistance are in play, hull, keel, rudder, and the hydro-dynamics of their interaction ie. lift or disturbance from a keel bulb. I believe that there are some modeling programs usedby naval architects to solve your problem. Try to contact: www.westlawn.edu
they're a school of yacht design and may be able to help or redirect.
Good luck, it's a long way from nice lines on paper to a sailing boat, but when it all comes together, it's worthwhile.