Used to be on a ship that would trim by the head ( 3' +) when fully loaded.
Put the engine half astern - back like a sumbitch to port (fixed pitch RH).
Even keel - half astern - back like a sumbitch to port. Trimmed by the stern -
half astern - back like a sumbitch to port.
Power used, is another one of those factors (otn missed that one) which will
increase propwalk.
It's not always easy to tell which factor may or may not be increasing or
decreasing or even IF there is any difference because of it.
For my money, the basic issue (propwalk) is caused by prop rotation and all
other factors may assist or decrease it, but the basic "phenom" occurs when you
rotate the prop.

Shen