"The " 0-degrees AOA to the relative wind", which you mention, may be Mart's personal feeling as to what would be optimal angle at the tip."
The easiest thing is to look at the history of fixed wing development. The Supermarine Spitfire had elliptical wings that enabled it to fly efficiently under all conditions. Concerns about manufacturing costs and tip stall in tight turns led the P51 Mustang to have straight wings, but with inbuilt twist so that the tips were flat (ie 0 degrees AOA). This lead to the P51 having an elliptical lift pressure distribution at cruise, but it moved away from this when pulling g for a turn or at higher speeds. Lets not forget all the Wright flyers which had wing warping.
My view is thus, to cover the largest range of speeds and manouvres would require straight wings, but with variable twist to keep tips flat rel airstream. The easiest way to accomplish this would be powerful tip servos, set at 0 degrees AOA, and a torsionally flexible wing. By altering wing root AOA you would get the most efficient and manouvreable fixed wing imaginable.
A helicopter blade is basically just a wing rotating about an axis. So once again for the least drag (or torque in this case) the lift pressure distribution should be elliptical (Prouty mentions this somewhere). The complication comes from the need to get this distribution from a wing that is flying slower at the root than tip. The best solution is thus to have the planform choord distribution proportional to 1/radius, in addition to the elliptical washout.
To cover the full range of flight conditions in any helicopter, this is why i suggest a powerful tip trim tab. This forces an elliptical lift distribution in all flight conditions. The nest result is low torque requirements.
Mart