>- should only have about 3.5 volt(notice the "about")
>- "The most important thing that a zapper can pass to the body is a fast rising edge of at least 5 volts"
Do you notice the conflict? A 3.5 volt output can not have a rising edge of 5.0 volts!
If you look at the web page Cheap Zapper, you can see that when attached to the human body, the ZP zapper only provides about 2 volts! As you stated above, this is not enough. Also, the ZP does not provide a fast enough rising edge.