The tongue length seems to be more of an issue on enclosed trailers vs. flatbed trailers. It can still catch the rear of the coach lower on the rear end cap but up top is the bigger issue. If a standard tongue is used with an enclosed trailer, you are turning and going through a dip there is a very high chance of catching the top of the trailer on the top of the rear end cap of the coach.
This is the reason most, myself included, recommend getting an extended tongue when ordering an enclosed trailer. Many trailer manufacturers actually call them an "RV tongue".
Mike.