An option is adding a mobile weighing system to your 4-way side loader. It can measure the actual load for example of a 4-way side loader with a capacity of 2,5 tons, up to 2 kilograms precise with a tolerance of ± 5 kilograms.
It weighs the load by measuring the pressure in the hydraulic lifting system. While dropping the load the pressure is measured a couple of times. This is translated by software to calculate an accurate load weight on the forks