Can you explain your last thought a little bit better? I'd like to catch on to your thinking there, because Stan does have a delrin cap on the top of the inner tube of the stacked resonant cavity unit, maybe.
About the + and neg voltage, I do think the water knows the difference between +1000 volts with -1000 volts, (case 1) and... just 0 to +2000 volts (case 2), and the reason is that it's not voltage that matters, but a "difference of charge" which is one step below voltage, and a little more fundamental
(case 1) you can have a piece of metal missing x electrons, compared to a piece of metal that has gained x electrons
(case 2) you can have a piece of metal missing 2x electrons, compared to normal metal that is not charged
now think about the water molecule, Stan talks about q and q', and coulombs law, opposite electrical attraction force, (case 1) gives the proper charge attraction and repulsion required for the forces on the water molecule, while (case 2) does not
also the chokes are a 1:1 mirror, the positive voltage going into the top choke will mirror it's waveform into the bottom choke with an equal and opposite voltage, the negative choke is connected to ground and to the cell, so the voltage put through it is referenced to ground meaning it has to have a negative voltage, in the sense that it actually pushes more electrons into this choke to accumulate the electrons as a charge difference
(case 1) and (case 2) are the same from a voltage point of view, but from a charge point of veiw they are different, and it's the charges we need to look at when targeting the water molecule
my take on it for now, anyway