I can't get this through my head, is the arrow rest in the center of the bow or is the handle in the center, or does it matter which bow you are building?
Recurve; I usually put the deepest part of the grip just about centered, slightly lower, and the shelf, about 3/4" above center.
Longbow, the grip center, the shelf 1" above.
On the case of a bamboo backed longbow, a self bow, or bow with an otherwise straight grip I attach a rest, about 1 1/8" over center.