In one sense you are correct. It is a function of amplitude. A longer tongue obviates a need of refined skills, much like a sawed off shotgun increases the probability that someone unskilled will hit a target rather than using a bow and arrow.
No amount of math will permit you to push a 2" fender washer in a prescribed path with a stick. It's just practice.
I did the practice.... spotted trailers for a LTL trucking company for many years. The math is: 30-40 trailers per night (on-side and off-side). I've dragged everything from a yard trailer to 53'ers. Agreed the shorter the trailer the quicker it can get out of shape and with less misalignment than longer trailers. It's a matter of having pride in developing a skill (putting food on the table or just executing a walk-off launch, never looking back.

) And when you hit one.... admit it, you get a shameless smug feeling, right? There aren't many things that will make a boater's chest swell than to have a sweating novice, with a complaining wife, and whining kids, ask you to spot their trailer for them. And you'll feel better if you don't take the five-spot that he tries to surreptitiously slip you.