All that have responded - thanks!
The rule of thumb being that tongue capacity is 10% of towing weight and that a TT tongue weight is 10% of total trailer weight has me at opposite ends. My 17bh is heavy at the front to compensate for holding tanks at the rear and my Rover is an oddball vehicle probably due to axle, suspension or just overall vehicle shape (tall and short). I will need to rethink my immediate plans - no quick trips south this winter, and may have to let go of a great toy.
Thanks again to you all!!