True if the goal is for the total volume should be 1 liter but men switch between balls for each ejaculation.
So the total volume should be 2 liters for it to work in our fantasy world where everything comes from the balls.
I just brute forced with some values https://www.omnicalculator.com/math/sphere-volume
The correct way is to isolate v and solve for r
You are totally correct, but I don't let facts interfere with a good shit post (or semen post in this case).