Bryan,
When Verner Von Braun talked about testing, it wasn't about the vague sensations of the pilot, but about measurements carefully recorded for analysis. And when he talked about expert opinions, these were only opinions, not calculation results.
The pilot's observation that his rotor tachometer at the moment of take-off, when the gyro is still in ground effect, is lower than the value measured a few seconds later when the gyro is out of ground effect, is true. However, ground effect is not in question, only the delay required for the Rpm acceleration:
Steady, there is only 1/2 rpm less because smaller angle of attack, the axial rotor thrust is very slightly lower to carry the same weight.
I desagree with your statements
* If a gyro at 3 feet uses less energy to spin the rotor than one at 30 feet, that extra "3' energy" can be used to deflect more air downward.
* More air deflected downward at 3 feet than at 30 feet explains why the rotor then "self-regulates" and lowers its RPM until Lift=Weight.
To spin the rotor the same energy is needed at 3 feets as at 30 feet. This is just required by the profile power, and it comes from the flow of air through the disk, as a wind mulle (Usually 3.5 m/s * S disk, giving the power of: Axial force * 3.5 m/s)
With no profile loss, no airflow crossing the disk required for to spin the rotor, at 3 feets as at 30 feets, and the A.o.A disc is only due to the need of downward deflection. So, A.o.A at 3 feets is lower due to the lower downward deflection.
* Induced drag is equal at 3 feet and 30 feet because lift needed is the same.
When the lift is the same, proximity to the ground reduces the induced speed. For the Xaviers' ELA at 45 mph the induced speed is 1.45 m/s OGE and only 1 m/s IGE. So, with the same airflow through the disk, A.o.A not need to be as large and therefore the induced drag is lower IGE than OGE.