GN all the way.
I've towed stuff that is illegal heavy (by a long ways) and all of my trailers are built as GNs
If the load is even close to even (side to side) then it will pull fine. If your load is so un even that you need a fifth wheel to ballance it-then you neek t reload your rig.
I have no problem with a king-pin and am not advocating to pass one up.
Just saying that I prefer a GN and have never had an issue with one handling the weight or stresses.
~Wes~