What happens when the reeds open :
the low pressure created which opens the reeds creates a low pressure in the carb .
the carb determines the mix (ratio of air to liquid gasoline )
IF--the reed opening time is short or long - the carb does not know or care -
IF------ the low pressure (signal)is very strong or weak - the carb does care .
reed stiffness will affect power available but the fuel to air mixture should not be affected.an overly strong low pressure (signal) should increase fuel flow but that would indicate that the carb size (basic venturii size) is too small.
So far --I can't find any real difference in top end needle settings of 201/76 -which would indicate that they both flow the same .
The 201 will choke more easily than the 76-at least on the ZDZ40/40 engines and it has more dischage orifices (3 vs 1) for low and you could say midrange flow.
IF there is any real difference it is in the high speed jet and frankly I can't see it if it exists .
someone must know if there is a difference in this part -that is my question.
the cover plate on the pump side are different we know that -
the zdz carb has a drilled tran sfer passage NOT found in the carbs using external pulse line.
so I can only note that the low speed delivery on th 201 is different -as a difference between the two carbs .
I simply don't know more about what Walbro may/may not have done in the high speed circuit.