Had an interesting discussion with a trucker at a truck stop one time.
I told him it was easier to back-up a rig with the rear axles close to the back of the trailer. Let him try to back up my trailer with the rear axles 15 feet from the rear bumper (42% of trailer length). He couldn't keep it straight, couldn't get it into a big rig parking spot. I got in his truck and backed it up perfectly the first time - having never sat behind the wheel of such a rig before.
I've also found a vast difference between my current trailer and the previous shorter one. The longer trailer with the longer overhang is harder to keep straight.
But as mentioned above - the key is practice. Learn how that specific trailer and truck combination back-up.
Now if I could just teach my wife to tell me to start straightening out in time to stop that a..end swing while turning into a spot.