How about trying pulling (dragging) rocks of an approximate known weight? With my CK20 the backhoe will drag or pivot rocks that must weigh about 500 to 900 lbs I would guess. I can move, over distances of several feet, by dragging, rocks that I cannot pickup with the loader due to excessive size, shape and weight. I think 700 to 900 lbs is the limit of the loader for rocks that will not sit close in to the bucket and that hang over the toothbar. Obviously the specifiction sheets state the exact limits of the lift for the loader and break out force I think for the backhoe buckets. I just put on some big foot pads on the outriggers that hold the tractor pretty good and let me pull the rocks toward the tractor instead of the tractor toward the rocks. Good luck trying to find a method to let you measure the dipper stick power.