Since you have a spinner, after you have traced the initial track place it in the bowl as Strider described using an ash tray. Turn the spinner on, if the line has any wobble in it adjust the ball position until it's steady. Then with the spinner running place your finger on top of the ball. Your finger will migrate to the very top of the ball. Turn the spinner off, leaving your finger in place, then mark the location with a piece of white tape. Take the ball to the lanes and throw it to be sure the tape stays stationary for the first 10' or so after you release it. -- JohnP