Reed valve design and function is very complicated and requires a lot of testing.  Total tip flow area is very important but flow is typically reduced each time a divider is added. 

The reed cage that has the least amount of dividers across the width of the cage will usually have the greatest POTENTIAL for flow, but the window may be too wide for some petals if they need to be a certain thickness to resonate properly for a particular engine RPM.

If the total flow area was the only variable, the best reed would only have one wide window on each side of the reed block "V".  With one wide window on each side of the reed block "V", the reed petals would fail all most instantly using the petal thickness that will have the correct resonance.  It would cave in because one large reed petal would not be strong enough when the piston is descending and building pressure in the crankcase. 

If we use "stiffer " petals to bridge a reed cage window that is slightly too wide, the resonance RPM will be raised and flow and power at lower RPMs will be reduced.  It requires a lot of testing to find the proper thickness and petal length for a given size window.  After window size and petal thickness have been optimized, the internal shapes have to be developed that will make the best flowing transition from the carb to the tips of the petal.

A engine that makes a lot of power has a reed that flows real well,  but a reed assembly that flows real well may not make very much power unless all the design variables are correct for that particular engine.