Only read halfway through this thread and started to get confused myself.
Just so I can clarify my understanding of the different topics, conservation of angular momentum surely does not relate to lead and lag, it applies to flare effects with regards increase of NR during the flare.
I was under the impression that lead and lag was as a result of the differing drag produced around the disc given changes in relative rotational velocity as the disc moves through the air.
As for static droop, it is caused by increasing collective pitch from MPOG to hover power where it is not compensated for in a governor. Any further changes in NR in flight caused by manouevering would be termed transient droop.
One way to explain conservation of angular momentum when related to flare effects is as follows:-
Imagine a flat rotor disc with an arbitary rotor blabe length which would produce a set figure for the circumference of the disc area. If you apply 'G' loading to the disc it will increase the coning angle of the disc i.e. in the flare. As the blade cones it slightly reduces the radius of the disc or the distance of the tip path plane from the shaft axis. This therefore gives a slight reduction in the circumference of the disc area as the radius is decreased. The blades momentum means it wants to travel the same distance round the disc in the same time but has a smaller disc round which to travel therefore it will travel further in terms of rotation whilst in the flare. The result is an increase of NR.
Feel free to educate me if I am too far from the mark, I'm always learning too!