Over a bottle of red wine one evening I told Eric that the spin recovery method he was promoting was consistent with the NACA standard spin recovery method - from memory, described as such in
Summary of spin technology as related to light general-aviation airplanes
Bowman, J. S., Jr. (NASA Langley Research Center, Hampton, VA, United States)
NASA Center for AeroSpace Information (CASI)
NASA-TN-D-6575 , 1971
Tail-design requirements for satisfactory spin recovery is the earliest reference I've seen to effect of the pause between applying opposite rudder and down elevator, although there is earlier work on shielding of the vertical surfaces.
Comparison of model and full-scale spin test results for 60 airplane designs refers to a desired spin "recoveries in two turns or less by reversal of rudder followed approximately 1/2 turn later by downward movement of the elevator".