Not to kick over the old anthill, but...
Same system, didn't have a bypass installed thanks to the good advice found here.
But now we want to install a humidifier, and we got a recommendation for the Aprilaire 600, which is a bypass humidifier that uses a 6" round duct to create a bypass. It has a manual (non-barometric) damper, which you open in the winter and close in the summer.
Since a bypass (especially one that's always open) will reduce the net airflow, is this a terrible idea, or is the bypass small enough that it shouldn't be a problem?
(Incidentally, the tech who came out said we really should install a bypass anyway to keep our zoning system from overheating. Sigh. If only I could find someone in my area who knew what you folks know.)