The Inflow to the disk is the place to screw with the air, because the losses are performed on lower velocity air, which causes less power lost (the drag force times the velocity is the power).
One prop took a rock hit on the first flight. That incident forever cast my view about pushers. Also, pushers work in a turbulent airstream, thats hard on the prop.
Nick and slowrotor, the above statements are probably very valid. To add to the above, the gyro community believes that the tractor configuration is more efficient than the pusher, for some reason(s).
Due to all these associated pros and cons, it seemed that the initial consideration should only involve the two actuator disks, and their relationship. That is why the web page mentions "The fuselage and aesthetics are not a consideration."
Dave, if you believe it is such a problem why not put the pusher prop above & behind the rotor to ingest clean air?
Mart, what you say may be valid. It may have an efficiency similar to placing the prop below & in front of the rotor. In both instances the disks are in parallel and the same air is not passing through both disks.
The disadvantage of the high prop is that the prop's thrust vector will be way above the craft's drag vector.
Alternately, just accept that there is one speed where performance is poorer, and only use prop above this speed.
Naughty, naughty. Got to improve the performance at all speeds.
Dave