When making turns, ignore the 2nd trailer. The long combination will subconsciously cause you to take turns extra wide. If you do that, especially when trying for a pull-thru parking spot, you will be too far over and stuck. The 2nd trailer will go almost exactly in the tire tracks of the 1st trailer. No panic stopping. When you apply brakes the brakes seem to take effect on the last trailer & tractor and then 1st trailer.
If you ignore the last trailer, the combo takes corners easier than s 53ft trailer.
When hooking up, if you back, the tractor steering must be straight ahead or it’s like trying to push a rope up a hill. Hooking up a set is the hardest part of doubles.