I spent over 9 years in Germany during the Cold War (Infantryman). I came to know a number of former members of the WWII German military. They were terrified of American artillery, much more so than the Russians who had more, but who did not have the American fire control system. The spotter was the lynchpin in the system. They saved my rear end on many occasions in my days in Southeast Asia.
Spotters favor heights for enhanced visibility. My dad was spotting in a forward position in a Jeep with a green second looey who allowed them to be silhouetted against the skyline. A German 88 crew took note and greeted them with a shot that exploded yards away, and my dad delighted in reporting that foolish looey crapped his pants, on his way to becoming battle-wise.