Washoutt,
The tip weights are there not to balance the rotor disc but to dynamically balance the blade against the MASTER BLADE on the whirl tower. The weights are located at three points on the end of the blade. The centre one takes weights to locate the centre of gravity and bring the final blade weight to that of the master. When the blade is whirled on the whirl stand and pitch applied the difference between the TRACK of the master blade and the test blade is adjusted by moving the weights from the back to the front or front to back studs. Also as the speed of the tower is increased if the track splits from the master blade the tabs are adjusted to correct the split. This is what makes the blades interchangeable and in the good old days before strobe tracking in flight you only had to set up the track with chalk on the blade tips and a flag slowly fed into the rotating tip path plane. I remember seeing the Chicago Aerial device for tracking which was in the S61 manual but never used it. The tower at Aerospatiale had an upgraded version bolted to the concrete base. You did not balance the main rotor disc on the Wessex but here was a Chadwick method used to balance the main rotor head on the S58.