Great, thanks for the information to at least DIRECT me which way to look at things.
Amazingly enough there was very little to be found on the "internets" about this, except a few studies that showcased a correlation between heli vibration and induced pain in the backs of pilots in some cases (must have been pretty bad).
I take it the MM's for most helicopters are not something that you could pull up from a PDF location somewhere. I also imagine they are probably very expensive to get (as controlled documents) so naturally, the owners dont want them out in the open.