Many stores already use copper or hyposalinity to deal with all new fish to help minimize fish loss. Critical factor for survival depends heavily on how the fish was initially captured - hand caught, cyanide (unfortunately), etc - and the shipping technique/process. If the LFS is willing to hold the fish, then slowly transition the fish into reef ready parameters (higher salinity/no copper), and keep it there for a month or more, I would be willing to pay more for the fish. Otherwise, I'd stick to my QT practice.