Extensor action is exclusively the steady effort to straighten the bent right arm. This stretches but does not move the left arm and produces a structural rigidity that is a strong deterent to collapse under the stresses of acceleration and impact. homer kelley
My opinion on "just enough" is dependent on tricep strength. Of the thousand golf swings I see each year would say the vast majority lack extensor action. However, someone like Wesly Walls, an x football player, has plenty. He has great strength in his right tricep and utilization for him is "just enough."
For the average player I feel it should be a Heck of a lot of push. Lynn talks about playing tug-a-war with the club. I personally like to feel a literal muscle "burn" when working on it because my previous stroke pattern had very little extensor action.
So the component of extensor action will vary in "feelings" among players based on physiology. Take a look at 12-3-0, it is mentioned SIX times! homer is saying "hello guys, take a look at this, it might be important."