You can download MTF curves for all Hasselblad lenses from Hasselblad.
You can be pretty sure that f/8 is a safe bet for almost any lens. Lenses with extremely good control can reach optimum at f/5.6.
The way this works that there are two limits to optical performance. Aberrations which decrease when closing down aperture and diffraction that goes up. So once aberrations are well corrected, diffractions sets the limit. There is at least one aberration, lateral chromatic, that is little affected by aperture. It is easily corrected in post.
Does one exist. Reading some of the posts around here and other forums I see contradictions of what is the best f-stop on the HC lenses. It would be fantastic if there was a chart with all the HC lenses and their sharpest f-stop listed in one place. Does this exist somewhere?