Spotting cars can be a trick and works well with a experienced crew. I have switched with anything from a SD90mac to the 463 and having a good guy on the ground is the key to success. You have to account for slack in a large train and how much it will roll and pull your locomotive. There are two schools in switching in whether to use train air or not, but a good guy on the ground helps so much!
You may be three cars away from a spot but a good man on the ground will tell the engineer he has two cars to a spot as the man on the ground is accounting for slack action and how much the train will stretch when it stops. A good crew who works together can make a day of switching fun and exciting where as the opposite can make a day drag on for what seems like forever.