Have you found Breathing Ladders effective with regards to training aerobic endurance? And have the alpinists in your midst found them helpful for altitude? Regarding execution, it seems like I spend a relatively long time on a breathing ladder session per number of movements. For example, the other day my buddy and did 45# one-arm dumbbell snatches ladder 1-20 in 38min - we ended there due to time constraints - which seems a lot longer than what I have found on your site.
Using the Breathing Ladders to train aerobic capacity in the gym is a stopgap measure, and due to the lack of specificity not as useful as more specific, more consistent work. However, there are several downstream effects that are beneficial, i.e. using breathing to send the "relax" message to the brain under stressful conditions, etc.
Some pointers: when using a single arm movement like KB or DB Snatch you may organize the work/breath in several ways:
1 rep with each arm = 1 breath
1 rep with each arm = 2 breaths
Typically we do the latter, which means at the 10 mark on the ladder one is doing 10 snatches with each arm (20 total) and taking 20 breaths afterward.
38 minutes is a relatively normal duration. We specify that, to have the appropriate effect the ladder should last 30-60 minutes. Recently we have seen a lot of guys reach the 50-55 minute mark using a 1-20-1 ladder with KB Swing (two-handed) or Headcutter. We made a guy quit last month because, having been a free diver who could hold his breath for over four minutes, he was at 17 on the way back down from 20 after about 70 minutes of effort. He would have gone on more or less forever. Usually, athletes with well-developed aerobic capacity can make a Breathing Ladder last quite a long time, especially when the movement, load, and cyclic rate are closely matched to the method used to develop their individual aerobic capacity. However, a mismatched load or cyclic rate can easily overrun the oxygen system, shift the load to the muscles, and reduce the duration of the effort.
One factor to focus on during the ladders is the clearing of CO2 from the lungs to make room for more (useful) oxygen to be taken on board. Often, especially during the shallow, panic-breathing period immediately after stopping work, we are only recycling the "top" level of air in the lungs and throat, while in the deeper recesses of the lungs, the air/gas is not changed. This simple emphasis on adequate exhalation will improve several factors affecting performance both in and out of the gym.