I too would love to hear from those that have tried new "safe" methods of protection. I have heard so many "old wives tales" of home brew's etc, but have never seen a follow up yet of whether the brew worked or not.
However, one positive, NZ outlawed tin TBT antifoulings about ruffly 15years(Give or take a few years) ago now. When TBT was in use, our loacl Marina's were baron of sea life and the water
had a strange hazy dead look to it. Today, the Marina's are now teaming with life. Small fish
, Ray's and Shellfish and interestingly, the waters tend to be clear and healthy looking. I put that last part down to the filtration that Shellfish carry out on the water
The copper systems don't seem to have the same visual impact on the marine
life, but I don't Know about what long term effects it may still have on the marine life. At the end of the day, copper is still a metal and it is it's consontration that causes it to work.