Chucking?

I would concede that leveling the trailer might have some impact on chucking but I disagree about your comment that lowering the front ride height increases the pin weight on the hitch. You can raise or lower the trailer a foot and it won't change the pin weight.

A foot may change the hitch weight very little but agree there is no changes in pin weight in a couple of inches.

Changing pin height may work for some combinations and may make it worse for others. I see where some (not all) either raise or lower the front of the trailer to help with their handling or help with chucking issues

Too many folks think what worked for their combo is the silver bullet for everyone else's chucking problems.

My 3500 drw 4wd crew cab chevy has severe chucking issues with a 36' tri axle GN stock trailer when loaded heavy on the pin.......but not with a 32' tandem dual axle trailer and the same hitch weight.
Stock trailers and flatdeck trailers can be loaded hitch heavy or hitch light. I pull them with two different size trucks. It takes several loads on each truck to find which truck/trailer combo will have chucking issues and which don't regardless of hitch weight.