Very impressive you are a craftsman.
I haul everything from fence building materials, concrete, lumber, etc. over hundreds of miles, no problem. I believe about 2000 LBS is the most I have hauled (25 bags of 80 LB concrete), and only about 50 miles. Trailer was around $2500 in 2014 I think. It won't ever rust, I can move it around easily by hand.
Here is a list of safety chain trailer laws
http://www.expediter.com/natm pdf folder/B folder/B3 6-State Safety Chain Laws-Table.pdf
IMO: You want to make sure they are crossed and underneath. You can take up slack by twisting the chain and try to keep separate length. In theory this should help keep the tongue of the trailer from digging into the pavement or ground should it become detached. Obviously not at the same height as the hitch but above ground level......although your trailer jack up front would keep it from going that far. Not all trailers have have a jack on the front.