The cocking and the uncocking of the left wrist is the #2 Power Accumulator in 'The Golfing Machine.' It works in a similar fashion as if you were using a hammer, so there really isn't a wide range of motion, just simple cocking and uncocking.
The left wrist should be uncocked at address. It then eventually 'loads' by getting cocked and then 'unloads' by getting uncocked. I guess you could say that most golfers 'load' the left wrist in the backswing as it gets fully cocked at the top of the swing. But there are golfers who 'float load' the club where the wrist does not get fully cocked on the backswing and actually gets fully cocked on the downswing (i.e. Sergio, JB Holmes)
Unless you have some other answer you are looking for, that's my shot at it.
3JACK
Make sure it's Level at Address. It will be Level at Impact, although it will be in the process of Uncocking.