If you increase the tongue length, you will increase the tongue weight
by exactly the amount of weight of the added tongue material. Leverage
has nothing to do with the tongue weight. If you move the axles
backward you will increase the tongue weight, forward will decrease the
tongue weight. Tom.

I disagree. A trailer is just a class 2 lever. If the distance between
the wheels & the ball were doubled, the tongue weight would be cut in half.