It seemed that the technique is not limited to just the steel balls as Gyro taught it to Johnny while under great injury and Johnny was able to mix it with Tusk to create a special technique that allows him to 'move' damage around in the form of holes and can even teleport his body through these holes, which can seek out damage.
The actual technique behind the 'Spin' is through the mathematical Golden Rectangle. If one continuously divides the rectangle into a square and a smaller rectangle, the angle which connects the corners of each rectangle will form an infinite spinning spiral. By aiming at this point clockwise, any thrown object can achieve the 'Spin' and cause a rippling motion in the flesh or surface of any person or object. The Golden Rectangle requires a reference that is in found in nature in order to be used, therefore rendering it useless in an empty room or vast flat ground.
Super Spin
This is the most powerful spin achievable. It involves riding on a horse and allowing it run until it reaches its natural speed and the horse will fuse with the user to form a large golden rectangle. With the velocity generated by the horse's speed and the large golden rectangle, the user's steel ball will be so powerful that it can literally cut things and numb the enemy's senses. Also, anything the steel ball hits will stick to it as is they were grown out of the steel ball. Stands generated via the Super Spin have also been shown to bypass dimensional barriers.
However, as the down side is that the horse is required to run at its natural speed, the technique requires a runway, similar to jousting. Also, this technique can be intercepted by killing the horse.