I'm hand-stacking on pallets in my cellar and trying to fit every bag possible on a given footprint. What's the highest you stack? If one 40x48" pallet has five bags on each layer, should I stop at 10 layers/1 ton, 15 layers/1.5 ton, or can I get away with 20 layers/2 ton before compromising the bottom of the stack? This site estimates a standard pallet can hold 4600 lbs, so the foundation isn't an issue.