One of my instructors, Tony Graziano Sensei (4th Dan), explained an interesting point relating to Kotegaeshi. If you picture Uke's "Ikkyo Curve" in your mind (the curved line between Uke's two outer shoulder points running across Uke's back), then picture that line extending out from the shoulders. As you apply your Kotegaeshi, turn the hand and move it on that line. It's unbelievable how much more effective Uke's compliance will be. It works especially well on a highly resistant Uke!
Or, another way, don't focus on the hand, focus on SHIKAKU (http://www.aikiweb.com/language/vocab.html)
. Positioning is far more critical than torqueing.