Yes, I've read what you said about the machines with multiple frequencies, etc., but this is why I'm looking at this model, specifically. It's a lot cheaper than the other models precisely because it can only run one frequency at a time, unless you manually re-enter frequencies. But, I told customer service I only want to run ONE frequency for an extended period of time -- he was surprised that I wanted to do this, since most people want to run multiple frequencies at once, but that this model only runs the one frequency you set it to.
Given all of this, do you think it's a workable unit, if I do, in fact, keep it at the 666hz frequency for 30 mins at a time? Note that it's not going to flip through frequencies. I just worry about the mechanics of it, or whether there is some other "addition" to the equipment that's counter-productive and would keep it from working well. If the issue is simply bogus frequencies, I can keep it at 666hz, perpetually.
Also, you said the electrodes are most effective -- with the machine in the link, these aren't electrodes, exactly, but metal tubes. The only difference that I see here is in the fact that the contact surface area is larger with the tubes, and it's uncomfortable to set your feet down on them -- would that mean part of the current will not be channeled effectively? If so, can this be gotten around by placing the tubes in a tub of saline solution, with the feet in the tub, on top of the tubes? Or should I get some kind of stainless steel foot pads, to which I'd attach the cables, like the pads being sold on the site: