The sphere diameters are:

Small: 50 mm Small Medium: 62.5 mm Medium: 75 mm Medium Large: 87.5 mm Large: 100 mm

The pictures above show the small, medium small and medium spheres.

The threads print best when oriented at the top, but setting up proper supports in this position can be challenging.

You'll get good results by blocking supports for the top two-thirds of each hemisphere and using the "tree" supports in Cura with a bit of brim to hold it all together. You'll still need to do a bit of post-print clean-up.