The grain of that board looks great. There is absolutely no reason to apply a backing. The hickory backing may even overpower the oak, which is not great in compression, and do more harm than good. If you insist on the hickory backing, it's OK. But I wouldn't apply it to this board. It's a waste of energy, glue and hickory. If you do back it, trap the backing and leave the belly flat. Shift the walnut lam from the handle to the center, creating a powerlam. The current thickness of the handle is way too much (1½" total thickness is plenty). The powerlam between the hickory and oak will help to stiffen up the center and prevent a popped off handle.