What the hell is the criteria? Best Pivot ...based on What?
Pivots vary depending on Plane Angle Variations, elbow locations, release points etc..
or are you going for what looks best!!!
Do you honestly think the pivot is the same for a Low Cut and a High Draw?
..If you think they are the same..you got a ways to go in learning this stuff ....
Honestly the Pivot in my opinion is over taught by most...
Remember there are 3 zones of action that have to be coordinated...
Teaching the Pivot is not really a difficult thing...but for the average guy folding shirts in the shop..it is probably SAFE...It's only gonna help..and not leave a mark..
Teaching people the release motions and moving the release point around to bring about better timing and application of force is really one of the many challenges...