One of the many tools we have available to us that we often over look are pickets. I have found that pickets can be used for more than anchors. When you are doing a low to steep angle evolution consider pickets as edge protection. I like to drive the pickets in one for each rope making sure to consider the resultant forces so that the forces on the pickets are inline with the pickets, then hang omni block pullies on each picket, once the team has gone past the pickets simply pick up the rope and put it in the pulleys. Then on there return trip up the hill when the team gets to the pickets simply take the rope out of the pullies and go past them. on large animals I leave a hammer at the lowest picket then then as the load gets close to the picket you simply pull the picket then take the hammer to the next picket and so on until you get to the top of the hill.