Differences you will notice immediately-
You can prove the effectiveness by noticing the swing of the pendulum.
It will increase by a visible amount with the application of tungsten nanospheres to the pivots and pallets.
If you lubricate the mainsprings with Tungsten Nanospheres, you will feel the difference right away when you wind the clock. Mainspring power is more consistant throughout its run.
Differences you will see over time-
Dramatic reduction in wear, pivots and bushings last much longer.
Pallets remain polished and escapement remains adjusted.
Mainsprings remain smooth winding.
More consistant timekeeping.
It is typical for the rate of the clock to actually slow after Tungsten Nanospheres are applied. This is because the pendulum motion has increased enough that the rate changes, so that recalibrating is needed.
The timekeeping of the clock will be correct once the clock is rated properly.