An excellent summary!
I think that the recommendation of not using lower levels of sanitizer when using copper and silver ions is a bit extreme, at least for pools. Killing most bacteria is very easy and requires a very small amount of sanitizer. It's the algae that is harder to kill and is usually what requires larger levels of disinfecting chlorine. With copper keeping the algae at bay, I think lower chlorine levels are OK. You still have to have enough Free Chlorine to allow for the reserve needed when chlorine gets used up (even locally) and perhaps that is what the studies and recommendation are about, but that's a different issue than needing enough to kill bacteria quickly.
Now spas are a different matter, at least with regard to the bacteria, Pseudomonas aeruginosa, that causes hot tub itch. That needs higher levels of chlorine to kill and I do not know if silver is even effective at all against this bacteria.
Anyway, I'm no fan of copper/silver ions as they are expensive and don't really save on anything. If you want to fight algae, using Borates is a better way to go and it cuts down on the consumption of chlorine (especially in pools -- we don't know yet for spas).
Richard (chem geek)