Coupla points:
1. Some have a tendency to leave an engine in gear through an entire
portion of a maneuver .... or, in short, too long.
Just go astern long enough to get the boat moving in the basic direction
you want. Since you know you will get an immediate propwalk to port,
have your rudder hard right, so that as soon as you take it out of gear,
what little effect the rudder might have at this speed and direction,
can be used and not overcome by the propwalk.

2. Be careful of leaving slack in a line and then getting sternway and
coming up tight on the line to get a particular maneuver .... you are
putting some potentially dangerous shock loads on the line and cleats.
Instead, maybe try different leads on the line you will use. In the case
of the spring, try longer and shorter leads and different locations on
the boat and/or dock, if possible.
Also, if you have help, have your line handler work the line .... you
can get sternway and still maintain a slight strain on the line, then
snub it ( I know, it's a shock load, but done correctly it can greatly
reduce that load) when you want to get a reaction (a good line handler
can make a bad docking look great and a great docking look bad).

otn