The more power you make the easier/earlier the weights get thrown out so you reduce mass to raise back up the rpm at which they are thrown out. Here's an analogy. You throw a baseball softly and it flies ten feet, then you add power/strength and you throw it 50 feet. Now switch up to a styrofoam ball and throw it with the same energy as your second throw of the baseball and it will fly a much shorter distance (10 feet?) because if it's reduced mass and same size.
Sorry I have to disagree here until I hear a better argument. Your is effect before the cause.
Honda is quite conservative with their stock weights so yes fitting lighter ones will give better performance up to a limit but that is not because the engine power has increased above its designed power, it is because you have allowed it to develop more.
The weights get thrown out by RPM not by power. If all else stays the same but only the power increases then the engine can carry a slightly higher gear than the lower powered one, so the weights can be slightly heaver to advance to a higher gear sooner. Example: If a 150 produces more power but at the same RPM as a 125 then the 150 should use heavier weights not lighter. All things being the same.
If all one does is change an exhaust there will be no change in the characteristic of the engine maybe a little more power but.... If on the other hand one changes the cam to push the power further up the rev range then lighter weights will keep the ratio lower longer to account for that.
If you change the ramp plate or a cheaper alternative machine different angles on the pulleys then the ratios will change at different times but still because of RPM not because of power.
It is a question of matching the RPM to the power curve. So if the right number is 7700 or 8000 then the weights go down until that is achieved. The power that the engine produces at that rpm is irrelevant only that it produces it maximum at your chosen RPM.