Never allow a shackle to be pulled at an angle; this drastically reduces its capacity. Use spacers if necessary to center the load.
You cannot rely solely on experience for Level 3; you need the math. rigger level 3 aramco notes
Aramco enforces a no-go (radius = load length + 5 meters) during any pick and carry. Level 3 riggers must enforce this, even against supervisors. Never allow a shackle to be pulled at
The configuration of the sling significantly alters its Working Load Limit (WLL). Types of Hitches rigger level 3 aramco notes
Aramco requires a Level 3 rigger to personally inspect before every shift. The notes contain a checklist: welds, gate latches, fall arrest anchor points (5000 lbs rating), and the anti-rotation device on the crane hook.