Here is a goal: How to efficiently park in the garage while using as little space as possible

How would you accomplish this goal?

a). With a spotter, pull the car into the garage as close to other objects as possible, and have the spotter tell you when to stop. Hang a tennis ball from the ceiling to touch the rear bumper of the newly parked car. In the future, pull the car in until the bumper hits the tennis ball.;
b). With a spotter, pull the car into the garage as close to other objects as possible, and have the spotter tell you when to stop. Hang a tennis ball from the ceiling to touch the windshield of the newly parked car. In the future, pull the car in until the windshield hits the tennis ball.;
b).