The "short pause" is not included in this procedure (it wasn't included
in the JAR-22 norm either, at least not in the last version I
downloaded). I called it "classic", however, because I read it in most
glider pilot training handbooks. The question is: where does it come
from, what is it's purpose, why isn't it included in the design rules,
what will be the difference in the spin behaviour, and last but not
least, how long or short is a "short" pause?

The following is what I was taught about that. I am not sure of it's
correctness and further discussion is welcome.

The purpose of the opposite rudder is to stop the spin rotation. The
pause is to allow time for the rotation to stop. The stick forward
unstalls the glider - at which point the glider accelerates and you
recover from the dive. If you unstall the glider before the rotation
stops, you are then in a spiral dive - which is preferably avoided.

It has worked very well on the dozen or so glider types that I've spun.

Tony V.
http://home.comcast.net/~verhulst/SOARING