Center of rotation/CoR figure of merit

Would it be possible to return a figure of merit for the various CoR methods ? I'm not asking for an absolute figure of merit, but at least a floating-point value which would indicate how good a CoR is, and can be compared to another CoR for a similar dataset and the same CoR estimator.

The main application I have in mind is for N-distance holotomo, where you need to select the best distance as a reference to perform the volume reconstruction (which should be the one where the sinogram is most suitable to the search for a CoR).

Of course maybe there are better methods to select the reference distance (like comparing how sharp the sinogram is when using each distance as a reference)..