Under Chilean load securing standards, what is the proper method for distributing heavy cargo on a flatbed or semi-trailer bed?

1. Concentrate all heavy weight against the rear tailgate
2. Distribute weight evenly along the chassis longitudinal center, placing the heaviest items low and centered directly over or slightly forward of the axles, securely lashed with certified ratchets or chains
3. Stack heavy cargo on top of light fragile boxes
4. Leave cargo loose so it can slide freely with the curves