You need a shape with a capacity of at least 800 - 1000 ml. It doesn't matter whether it is box-shaped or curved. Here it is a "saddle of venison baking pan". For the mango hood, measure the entire length, height of the walls and width of the floor within a box shape. In the case of a semicircular deer back shape, measure the inner length and then place the meter tape from one upper longitudinal edge to the other and into the hollow. So you have the size for the hood. Correspondingly, then, on a smooth surface, smooth out a slightly larger piece of cling film - as free from creases as possible - and record the determined dimension there.