The Best Answer for Which trailer has more downward pressure where it attaches to the car ?
This is often a matter of how the trailer is loaded. If you put too much weight in the back of a trailer you can make a negative tongue weight and the trailer will lift the rear wheels of the pulling vehicle, possibly enough to make you lose control as you go downhill.
In general a single-axle trailer is more sensitive to load placement than a two-axle or three-axle trailer. We have several horse trailers, and they are all two-axle designs, because horses tend to move about in the trailer