There has been a lot of discussion about tongue weights et.al.
One factor to keep in mind is the effect of hitch
weight on the tow vehicle
axle loads.
As long as the hitch ball is behind the rear
axle, any
weight applied there will cause a transfer of
weight from your front
axle to the rear axle.
Think back to high school physics and simple levers.
For example. My Highlander has a wheel base of 109.8 inches. The hitch ball is 42" behind the rear axle. Our trailer has a hitch weight of about 250 lb.
Multiply the hitch weight by the ball distance and divide by the wheel base.
That will be the weight transfered from the front axle to rear. Add it to the hitch weight to get the total added to rear axle. Subtract it from front axle for the reduced load on the fron tires/
(250 x 42)/109.8 = 95 lb 95 + 250 = 345 lb add to rear axle. subtract 95 lb from front axle load. Adjust tire pressures accordingly.
A fifth wheel or gooseneck trailer; with the hitch point over, or a bit ahead of the rear axle does not cause any waeight transfer.