I still don't understand what you mean by 'trail hand below'. In 'racing round' from 6/100s to reverse mirror the trail hand follows the shaft so it starts (hopefully) on level with or above (vertically higher) the lead hand, goes below (vertically lower) and then goes to slightly above (higher bertically).
I also don't know which question from petearm you mean relative to this.
Close your eyes and swing using inertia pushing and retaining. In the first case I feel the trail hand going below the lead hand through ‘impact', when retaining I feel as if the trail hand stays above the lead hand. Just peek below in the thread - "I did not release at all". Petearm has a similar sensation.
P - There is no explicit active rotation of the lower body in Bertholy.
B - To achieve this, these remarkable men make what I call the ,"Vertical Drop", and then once this has been done, the "HORIZONTAL TUG OF THE LEFT ARM", was accompanied by lower body leverage and spinning.
I don't know how to read this otherwise than as a sequence of drop followed by left arm tugging and lower body torqueing.
