I make most of my spheres by "feel".

For small to medium spheres I have two methods:
1. I start a flat coil with the closed circle in the middle. I make that
coil out to about he width of the sphere i have in mind.I then use a wooden
spoon i have re purposed to push out the center. I push and shape a bit to bet
me the first half of the sphere, with the spacing as i want it. I then make the
second half winding down to the center. When done it is all fine tuning.

2. I make a spiral like the first half above, say in a counterclockwise
direction. I then start a coil winding in from a clockwise direction, giving me
an S or 8 shape. Push the interior of each out and fold into each other to make
the sphere. (this is good time to put something in the center, and fine tune.

Good luck.

Thinking about this is giving me an idea. Maybe I will make one and provide a
photo-how to.