A healthy corset press the front of the body up. But to make a pressure up the corset have need of a base too make the pressure from.
Two bases are possible: The hip and the shoulders.
If the corset been pressed up by shoulders brace, the braces have need too been broad, too spread the pressure.
If the corset been pressed up by the hip, the hip part of the corset have need of large broadly too spread the pressure.
If the corset do covering the chest, the top of corset have need of a separate lace, because the chest have need of space to grow when the waist been tightened.