What I found is that you must use both copper paddles and footpads at the same time plus, you must use a zapper that is strong enough to provide a good clean signal through the lower resistance.
The proof that this works is that after zapping, you must replace the bacteria in the intestines or you can quickly develop Candida overgrowth.
I have built an electrisation device which is 4 times more powerful than yours (yes 48VDC output) and even if i have used 4 copper electrodes with wet cotton clothes on it, and even if i have used it during several hours, during several days, and even if i have tried different frequencies (15Hz, 666Hz, 1000Hz, 2500Hz, 10000Hz, 30000Hz), it does not produce much die off...
Then about your claim that the electric signal (with the frequency which is supposed to kill the helminths with magic harmonics) can reach all parts of the body uniformly, this is nonsense in theory because a current is always supposed to travel through the path of less resistance, and of course sometimes it will spread a little, but it has no good reason to spread in all parts of the body, and i can prove it in practice : put the negative electrode on one temple and the positive electrode one the other temple, you will see "white".
If the electric signal was spread uniformly in all parts of the body, you would see white when you hold the electrodes on the palm of your hands or on the sole of your feet. This is not the case even with a higher intensity signal.
And then about the supposed die off your zappers produce, you have killed tiny bacterias in a jar of water and you assume that it will kill big adult helminths. You are not objective. Show us the proof that your zappers manage to kill big adult helminths in all parts of the body. After all these years of selling zappers, you can't.
To comfort you, there are plenty of other zappers sellers who spread more nonsense and lies than you. For example those who recommend to use wrist wraps with 1MOhms or 1kOhms resistance... It works because most people don't understand anything about electric signals and they think it is a high tech futuristic magical practical cheap treatment (compared to many doctors who ask you to do many tests and then tell you that you are ok) I was one of them some years ago. I feel better now. Happy sales !