I work at a nursery in California where we go out and plant the trees that we sell. Some of these trees are in 36" boxes and weigh up to 1700 lbs. Many times customers have 3-5 feet retainer walls and don't want to pay for a crane, and the planting crew is forced to hand lift these boxes inch by inch along a make shift ramp. I figured it would save a lot of time and money if we just built our own pulley system. Any suggestions on schematics or possible solutions to the problem?