Well, talking to more people "in the know" it seems that the best Colloidal Silver generators (e.g. silverpuppy and silvergen) all use a constant current source, not a constant voltage source like your 27V or 30V circuits. But it's the current density that is the critical factor. I think I'm going to have to experiment to get it right.
Apparently it is the silver ions that do the good work, so making monatomic silver would be a waste of time. Apparently those websites that suggest otherwise are cons. Who knows? I didn't say I "could" make monatomic or diatomic silver suspension, but I was thinking of giving it a try. I did an MSc in materials Science and my supervisor has a lot of experience with materials stuff (including silver) so it seemed like a fun problem to try crack. But it wouldn't be easy at all so I doubt it's worth the effort if monatomic silver is not antimicrobial. Rather I think I'll try make a really good constant current Colloidal Silver generator so I can drink tons of the stuff. That said, creating tiny silver particles sure might be fun. Who knows, maybe they do kill things.