Tom, that in-depth analysis is great. If you take a cross section of the dual runner twin ports, and compare that with a single oval, you might conclude that the dual runner manifold is going to flow more.
One more twist on this is the length of the runners (two different lengths with two different diameters on the dual runner manifold) as well as the end tank volume. Don't forget the two pipes from the TB to the end tanks on the dual runner.
Just for this scenario, lets assume the throttlebody opening is the same.
In the end, the thing that really matters is how much air can effeciently be pushed into the head at a nice range of RPM's.
Ooohhh.... How about the 3 stage Jag X-type intake manifold?