[KevCarter]

Here is a really good explanation tying to Jeff's video I found from Drewitgolf:

As Mike correctly pointed out, hang your Plum Bob (line) from the point where your #3 Pressure Point would be and the weight will pass through the Sweetspot which is a pin point (contrary to what club manufacturers tell you). The Sweetspot LCOG is On Plane. The clubshaft, however, moves from its own Plane to the Sweetspot Plane and back to its own Plane again. So the Clubshaft Plane is always shifting between its own Plane and the Sweetspot Plane. This can be a little confusing.

I think understanding that we need to monitor both sweetspot plane, and shaft plane, while understanding the difference is key...

Kevin