Reply #5: If your shelf or shelf standard is big enough.... [View All]

[Schema Thing]

to cover the void visually, don't worry about putting anything back in the hole. Whatever you do is only going to be for visual, as opposed to structural, purposes. The screw into the stud is going to take care of the mechanical part of holding the shelf up. I can't imagine that once your shelf is up, a little spackling wouldn't fill any remaining void, and look the most natural to boot.