It is important to understand how the layout of wood in an interior space should dictate your woodgraining. Knowing and abiding by these rules will show that you are a professional who respects the laws of fabrication.
When dealing with a large panel area, it is important to research the type of wood you are graining and the size of the tree. The dimensions of a board or plank of wood are limited by the size of the tree trunk from which it is cut. For example, a tree that is 4 feet in diameter will yield at its widest point, a a 2.1/2 to 3 foot-wide board (after the sapwood and bark have been removed). As a result, a large panel must be divided up into several smaller boards, usually of equal width. Sometimes a smaller area, such as a panel within a door, is divided into two unequal-sized boards whose dimensions are generally equivalent to 2/3 and 1/3 of the width of the space. I like to divide my panels into an odd number of boards, if possible. I believe it is more pleasing to the eye.
As far as the length of the wood – though there are no standard lengths of wood, a maximum of 12 feet is recommended. Some types of wood are available in smaller dimensions. For example, BURL is generally cut into veneers no larger than 1.5 foot squares. It is important your woodgraining reflect these natural installation parameters.
See this drawing of an interior space constructed of wood.
In general, the central panels should feature figure graining, while the stiles and rails should be composed almost exclusively of straight graining with only partial figure grain visible. In contrast to marble, the stiles frame the rails. On the panels below the chair rail, the woodgrain looks best horizontal when the panel is wide. Or vertical if the panel is square or narrow.
Know your species of wood, how it is cut, and how a carpenter would install it.
See also our previous post on Nantucket blue oak.