I have one of Ken Presner's zappers and tried to get one of those big tapeworms with it. I was also taking the Zymex 2 at the time, so really can't say it killed any big parasite. Maybe it helped. Hard to say because I have never stopped the Barefoot dewormer since I started all this. So this wasn't a very controlled experiment. What it did do was keep me from coming down with a cold once.
My usual time was 20 minutes on, 20 minutes off x 3, twice a day for a while when I had lots of the parasites to get rid of.
Hope this is of some help to you.