bottom contors

Plan around 6’ 8" forward of center single pintail. Plan to dome the deck for glide and early entry to 3" problaly. More of an area pintail than a narrow blade. My thoughts and questions are such Rails, down allround and hard upto the middle 3rd, but open to suggestions Bottom contures–perhaps a very slight belly in the nose to v.slight double concave in tail on either side of fin. Should the concave be paralle to rails? Should i just make the whole bottom flat? Nose & tail widths? Alternate Rail plans? I am well accomstomed to singles and twins, but not modern thrusters. The plan is that this will be my larger point surf board, head and up, especially the Wall down in Baja & pleasure pt in S.C