I got an above average backing ability; I can do it with or without using mirrors, depending on the mood of the day. Just don't depend on me doing it one specific way. I learned most of my backing skills when I had a f-250 supercab long bed, slide in-camper, a 19' boat and a single lane driveway in town on a busy street.
I would park in the church parking lot and wait until late evening when the traffic slowed down. then try to quickly get it stabbed into the driveway; using the small mirrors. got pretty good at it and never hit anything!