DKjens
I'm sure your pilots manual is correct. I'm an old retired aeronautical engineer but I'm never looked at the various comparative contributions of the rotating prop to torsion around the 3 (x,y,z axis) either on full scale or models other than to recognize it's there and must be taken into account. I have designed from scratch one full scale prop driven single engine plane and done all the performance analysis but it never got beyond paper and I didn't consider the torsion effects of the prop other than to make sure my Vmc numbers were probably correct.
Having said that I really don't know the comparative torsion effects of prop wash on the fus, on the wings. "Pitch" factor or GP. My gut (often wrong) tells me that on full size, especially aerobatic or heavy metal (prop war bird) GP would be big because of big heavy props. GP I'm sure is used by full scale aerobats to the advantage for many manuevers i.e. spins. Having GP pitch the nose up when applying left rudder would seem to sure help spin entery and transition to a flat spin. And I would guess that GP is a much greater force to deal with than "Pitch" factor . But I really don't know. On a model I would guess that pitch factor is the greater contribution because of the small mass of the prop. But I really don't know. Many of us are using heavier APC props now and that could be making GP a bigger factor.
I suspect that Ollie may be an old aero guy too and probably much more practiced than I. Maybe he can tell us something here as it applies to models.
Now I'm going to have to take one of my aerobats out and try to see what effect switching between wood and composit props has on trim while maneuvering because before I haven't even given it any thought.