Labeling Automation Options
LabelVisibility is an option for Callout and is used to specify priorities for resolving label conflicts.
Compare the sizes of Jupiter's moons with planets.
By default, the label conflicts are resolved in the order of data.
In this case, body radius can be specified as LabelVisibility via LabelingFunction, since the interesting fact is that Jupiter's largest moon is larger than the smallest planet.
Use LabelingSize to limit the size of labels. For images, labels are resized and larger versions are shown in the tooltips.