Tongzilla is correct in his response regarding the use of Pressure Point #3 to create Extensor Action, especially his comment regarding inhibiting the Left Wrist Cock.
Personally, except for Extensor Action Takewaway, I find it much easier to create (and teach) Extensor Action using Pressure Point #1 (the heel of the Right Hand pushing against the Left Hand thumb).
It is particularly effective to feel this 'Right Arm Pushaway / Left Arm Stretch' at the Top. Practice daily the Start Down Waggle while applying Extensor Action 'Push / Stretch'. The combination of the two is the first Check Item at the Top in the Mechanical Checklist For All Strokes (12-3 / Section 6).
I have to agree. I've said before to use the #3 pressure point and right hand thumb, but the harsh reality is that the direction of stretch is more or less On Plane. The #1 pressure point directs the extensor action below plane where it belongs and is unwavering during the Takeaway and Backswing. The direction of pull seems always down the left arm (wherever the left arm is pointing) and, there is less confusion in the duties of the #3 Pressure Point.