Here is my 4-panel juggling ball pattern piece:
This juggling ball pattern math is pretty simple.
What would you like the circumference of the ball to be? _____ inches/cm
Divide that number by 2: _____ inches/cm
This is the center length of the long side of the pattern.
Divide the center length number by 2: _____ inches/cm
This is the center width of the short side of the pattern.
Add an even seam allowance around all edges (I used 1/4 inch).
Since each long side divides the ball in half, and each short side divides the ball in quarters:
long side length X 2 = short side length X 4 = ball's circumference
So you should be able to make any size pattern you like. I suggest taking your pattern paper and folding it neatly into quarters, then measure up half your long side length (plus seam allowance) along one fold from the folded center, half the short side length (plus seam allowance) along the other center fold, then cutting one nice curve from one measured end to the other. Then your curve will be even on all sides of your pattern piece when you unfold it.