When I box a bike, I always build the box around the frame. However, I keep it rectangular. The corners are super reinforced and I use smaller boxes inside to hold small parts while those boxes also act as structural supports for the corners and the middle. If your having hard time visualizing, think about though tripods that pizza delivery places use to support the center of the box so you don't get you topping smashed all over the cover. My packaging is extremely minimal, but stronger than just about every form of packaging I've received.