I understand how the wiring is easier but I don't understand how the plumbing is.
When we mount the valve close to the cylinder we only have to run one hose up to that area instead of two. To me this is simpler, cleaner and uses much less air. But to each his own
Cv will vary according to the pressure used and even temperature, it must be calculated for every given situation. It is a poor value to use for our purposes.