If you read back through this and other threads, it's pretty clear that PZ has tracked the performance of several Zapper designs. Makes sense, since he wants to see how he is doing against the competition. I don't recall any other Zapper manufacturer presenting the volume and depth of data PZ has.
I haven't had my hands on any commercial units. I have experimented with a variety of zapper circuits, mostly to see how they vary electronically. My big question is not *if* they work, but *why* they work. Is it the fundamental frequency, number of harmonics, output voltage, high-frequency drive capability, current (or constant current)? It probably is some combination of these parameters, but it sure would be nice to know which ones.