Hi there, I m new to this forum, but I ve red this thread with some attention, and you don't talk about recovering silver using piece or powder of copper.
Is it possible that after precipating the silver on the copper , filtering it and put everything (part of the filter also) in nitric acid it should remains some Copper and Silver Nitrate, and put appart those two thing almost easily (I know how to do this actually but never done it ), and then cristalise the silver nitrate to re-use it .

I m doing wetplate and albumen print and I can get a lot of old fixer (I took 10liter just to try during holiday) , with tetenal fixer test strip I can read that they contains almost 7gr/L of silver, so maybe it worth it ?