Now that I feel that I have a good understanding of counterweight stalls I am sharing it. I'm compiling a very detailed and hopefully useful page about counterweight stalls. When it is finished I will write one for arm stalls and hopefully sort out some sling equations I have been working on. I'm trying to get information about how various parameters effect the amount of energy transfered from the arm to the sling. If I can do this, I will start to be able to determine how one would get the optimum leverage profile for a given counterweight drop and mass ratio (maybe some other parameters are needed). Armed with this information, it will be much easier invent more efficient design that can maintain efficiency with higher drops and mass ratios.
Basically the plan is to understand the CW to Arm energy transfer enough to manipulate it to get what we want, then understand the arm to sling transfer figure out what we want from the CW to arm transfer timing.