Thank you very much for the information. I guess what I can
do is put a load on the front of the trailer and see if that
helps. I wasn't sure whether the fishtailing was a symptom
of front overloading or front underloading. This was a home
built trailer so it's proportions may be questionable. In
thinking about it, could it be that my hitch is higher than
it should be? That could tend to take weight off the tongue
and even raise the front axle wheels. Is that right???

Again, thanks. sdh.


Yep.
The trailer tongue should be level or angled down toward
the truck. (Front of the trailer lower than the rear).
A lot of tall 4x4's don't use the proper drop receiver
and the tongue is sitting way up in the air.
I tow a travel trailer with no antisway or load levelling
and the trailer is very stable.
I was behind someone towing an empty trailer. It was
bouncing up and down. I swear I saw the truck & trailer
go perpendicular to the road heading toward the ditch.
Somehow he saved it and kept bouncing down the road.

Wayne D.