If your confident that your fish are ok ( personally I would go longer) you can do both. water change will lower your levels and you can use cuprisorb as well . Because it’s a 10 tank pay more attention to matching your water that you will be replacing to the same parameters as the quarantine tank water . Temp as well . I personally on a ten gallon would be careful not to change too much to fast I’m guessing 30% first the about 10%every other day keeping a eye on them . What type of substrate do you have in the tank ? Given that you have some type of substrate I’m guessing rock the only way to be sure you remove all the copper would be to test for it . If you don’t have a way to test you might call your lfs to see if they have . If not after a week of water changes and cuprisorb take the fish out and acclimate to the display tank water in another container then after acclimation I would first dip the fish in another container full of tank water to make sure your not putting copper in the reef display tank kind of like a rinse . Don’t put the quarantine substrate in the display tank . Good luck