I use the Seachem test kit. I know other people who use the Salifert.
If you are going to use Cupramine, I would treat for the recommended duration of 14 days. You can use the prazi at the same time. I do a 50% water change on day 8 when using prazi. Make sure to redose any water that you add to the tank. Its a good idea to have an observation period of at least two weeks after treatment, just in case the treatment missed anything, but then I tend to be a little overcautious. I like to wait until the fish in quarantine are eating before adding any medications.