I readjusted the second stage, closed up the cans, put a hose on and tried it on the bench. There was a nice improvement in performance. I then took it apart and reinstalled the washers and tried it again. We're cookin' with gas now! Holy mackerel ! Can't wait for Lake Michigan to calm down for a real test. So, especially if you have been diving for a while, make sure your second stage is set properly and you will be good to go.
That is why I posted the pictures about the lever height and three posts earlier I was talking about checking the cracking effort.
The venturi flow is an aerodynamic flow pattern that creates a relative vacuum at a point (area) where the flow has being accelerated, in this case by the jet exhaust of the second stage. That vacuum in this case will assist in holding the diaphragm down, but that will only happen if the force required to hold the diaphragm is low enough. That is the reason why a low cracking effort is still required.
Having a low cracking effort in combination with a reliably powerful venturi flow will provide the best stable performance in a double hose regulator. And to take advantage of that venturi flow, the flow diverter will direct the flow into the divers mouth without any blow-by wasted air.