Graviman,
For a start you will always get upwash (fountain effect) in the circle (rotor planform) of zero velocity
Where did this statement come from?
Just in case it is reverse velocity utilization that has lead you to the tri-teetering hub ...
The tri-teetering hub is an attempt to give greater control authority to very light rotorcraft. It is not intended for high-speed flight.
This Lockheed article from the first Issue of Stu Field's new magazine Experimental Helo might be of interest.
Dave