[BerntR]

Airair,

It looks to me like you're about to get this part.
There isn't any difference between what happens with Accummulator #3 and dual horizontal hinging. Dual horizontal is one way of releasing the club, including acc #3.

There is a difference in how acc#3 is released with dual horizontal and angle hinging, but I guess you've heard about that already. In dual horizontal, the release is sequenced: 1->2->3. Like a chain reaction if you wish. With angled hinging they all happen at the same time: 1+2+3. The dual horizontal hinge has a mechanical advantage because it is the hinge action that has the longest clubhead travel compared to hands travel.

Dual horizontal is also the hinge actionwith fastest overtaking rate.