The weakest point of the construction is the steel cable, I estimate the tensile force at 250kg based on the thickness of the steel cable, as I do not know exactly what kind of cable it is. I regularly load my pulling station with 200kg and it holds it.
Additional disc weights are required for the "wall-mounted lat pull-down tower" from Gorilla Sports in order to adjust the resistance on the cable pull. The device is suitable for weight plates with a hole diameter of at least 25 mm and the resistance is adjusted by adding or removing these weights.