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Re your point #1: I think that they are referring to the response of the helicopter not the disk. Prouty says that a disk will respond within one revolution. Note that he is probably not considering the Robinson.
Re your point #2: Yes. Theoretically, with a delta-3 of 45º, ever degree of positive flap change will result in one degree of negative pitch change. The moving locations of the various flight-control joints, plus dynamic effects, will change this theoretical purity.
Re your point #3: Yes. This is the same as what you have been saying all along.
