CBE, ASC, BSC
As others have already mentioned, contrast ratio is a creative choice based on how dramatic you would like the scene…all true but it’s not always so philosophical or up in the air.
The key to fill contrast ratio chosen for your subject should be an extension of the light in the entire scene. If you have the lighting or abilities to control your entire frame, do so and then light your subject accordingly.
Given that this question seems to be an approach to the subject alone, let the light in your scene determine the contrast on the face.
