Jimbo, you can do what you are proposing, and it will improve the sound to some degree.
The improvements, however, will come from the lowering of the center of gravity of the counterweight, and not from increasing the horizontal mass component of the tonearm. This is because when you increase the mass of the counterweight by adding the lead tape, you will have to move the counterweight closer to the pivot in order to balance the cartridge. As such, the mass components as the cartridge sees them, will remain the same, or at least very similar. But lowering the center of gravity of the counterweight by adding the lead tape will improve the tracking of the cartridge and I suspect the improvement will be audible.
Due to the things I mentioned above, I think that adding the lead tape at the very bottom of the counterweight would be the most productive place to put it, in terms of making the most sonic improvements. If you have to make several layers on top of each other, to get the desired effect, then that is what you should do. Bringing the majority of the counterweight mass down near the level of the platter is known to improve the tracking performance.
However, I don't think that it will do anything for increasing the horizontal mass component. But hey, any improvement is worth doing, right? It's innovative, and cool to do your own tonearm mods.
The improvements, however, will come from the lowering of the center of gravity of the counterweight, and not from increasing the horizontal mass component of the tonearm. This is because when you increase the mass of the counterweight by adding the lead tape, you will have to move the counterweight closer to the pivot in order to balance the cartridge. As such, the mass components as the cartridge sees them, will remain the same, or at least very similar. But lowering the center of gravity of the counterweight by adding the lead tape will improve the tracking of the cartridge and I suspect the improvement will be audible.
Due to the things I mentioned above, I think that adding the lead tape at the very bottom of the counterweight would be the most productive place to put it, in terms of making the most sonic improvements. If you have to make several layers on top of each other, to get the desired effect, then that is what you should do. Bringing the majority of the counterweight mass down near the level of the platter is known to improve the tracking performance.
However, I don't think that it will do anything for increasing the horizontal mass component. But hey, any improvement is worth doing, right? It's innovative, and cool to do your own tonearm mods.