I'm going to try return to that article when I have time to read it and maybe do some extra research to come up with some hard numbers.
But off the cuff, I think calling yourself "ethical" just because your materials are recycled may be at least hyperbolic. There's a lot to think about in terms of both environmental impact and your raison d'être as a designer-maker or whatever you call yourself.
I'll be very open about where my materials come from so prospective buyers can make an informed decision. I won't be going out of my way to claim a moral high ground; this in itself is interesting given that morality and ecology are now often conflated in the marketplace, with many dubious claims in the mix as individuals and companies try to seduce consumers.
Thanks for the link, I'll try to get to it.