Yes, the position of the hands is important, it is through the hands that feel is transferred to the body.
What Powell is apparently implying is that the right hand has a role in the perception of feel and gun types that put the gripping hand (right hand for right handers) a little further back improve the feel. By contrast gun designs that have the right hand closer to the action body give a less lively feel. Action types with lock work behind the action body, ie sidelocks, trigger plate locks, sliding breeches, by necessity put the triggers and the gripping hand a little further back.
I will add a personal observation: boxlocks with a longer rearward placement of the triggers, seem to handle a little better than boxlocks with the triggers closer to the action. Compare a Westley Richards boxlock double trigger with one with a single trigger for instance.
The problem is to get one of each of the above types of actions in the same place at the same time and compare. I have handled them all, but one at a time. If there is a lucky soul that has one of each they can compare and tell us.
