This is all making me think more and more that a one-into-four construction for the charge carrier-inlet leaders might be a better approach, space permitting. This would do away with the plenum altogether, and perhaps reduce the chance of uneven amounts of charge being delivered to each chamber...
Would it be desirable to follow the air flow pattern and see in what way it enters each bell mouth? Depending on the shape of the entry port to the plenum, I'd hazard a guess at the furthest bell mouth (let's call it number 4 of 4, at the far end of the plenum) receiving the highest volume of...
