Its definitely not relaxing after everything is set, just like you say there is no point in relaxing and un-doing all the necessary tension that was just set up.
Initial relaxation as a baseline then adding only what is necessary (which yes is a decent amount to shoot fast).
Adding pressure at the hands without adding tension at hand muscles, sorry didn't mean use no muscles and tension at all and be a big blob
-If you put your finger inside a nut cracker and close it, the most efficient point would be to operate it at the very end of the arms to get the greatest effect with least input (leverage). The clamping force is being derived from a different location of where the actual clamping point is, being applied through leverage