I came up with this rigging method a couple years ago and have been using it with great success. No matter how low the stage pressure gets the stage remains in the same position. Notice the position of the stage at the beginning of this video and then the position it takes when clipped onto the line. It takes a little practice but after about 3 times of clipping and unclipping it I had it down to where I felt comfortable doing this in a cave. Finally got someone to get some video of it.