All enclosed volumes need to have reasonable powder evacuation holes. The loose, unprinted, powder needs to be removed from any enclosed volumes or that volume of material needs to be charged for. A single 1/16" hole will not suffice for powder removal. The larger the hole and/or, the higher the number of them, the better. Because you are far more familiar with the design and design intent, you are more likely to place the holes in the most appropriate locations. LGM can also place appropriately sized powder removal holes in your model, but that service will add to the cost of the model.