Having less cluster being streamlined is one part the other is minimizing CL volume and making it closer to your max inhalation volume. Although that said it is not a substitute to practicing and maintaining CL volume to the minimum volume you need at any given breathing rhythm, regardless of total volume. CL are made to fit largest range of people so as to simplify manufacturing, and need to be at least large enough that if the diver needed to work hard and started panting he could get enough gas with out firing his dill valve at every breath, and not run out of Dill during the dive. Even though as we all know breathing hard on a Rebreather is bad practice as we can possibly create problems in the scrubber.