Flytest
The mass balance is (see previous remark by Nick) apparently very important in mastering the torsional disturbances. Adjusting the tip weights (in all directions) is part of the total mass balance. So it should help but will not be capable of providing for all the control the weight distribution and concentration provides for over the full blade (both in span and along chord). The blade end does however not enjoy the same 'preferred' position with respect to torsional disturbances as it does for flapping disturbances, because the centrifugal forces don't play here.
This is similar to the multiple bearings of the tail-rotor shaft, where several bearings are needed to provide for stability (of torsional nodes)
Delta3