I have been following your thread and just signed up to say sorry for your loss.
I'm also currently completing a 76 day fallow but I am completing TTM instead of copper, I have had bad experiences with copper in the past.
My gamble was after having a almost 2 year ich free tank I decided to add a Powder Blue Tang to my tank, he went through 3 tank change through TTM and wouldn't eat and I was very worried about his behaviour in the QT so I skipped the last (4th) TTM and now i regret it..... I have learnt my lesson too!
Thanks for tagging along, and for the condolences. I'm still hurting from losing him, but I'll try another soon. It's one of my favorite fish.
I hope your fallow period goes well and all your fish make it back to the display!