I have tried Stop parasites. For me, it helps ease the severity in less severe cases, it is not a treatment as such. Copper can be pretty harsh on fish.
Good ol hypo will control WS within a day or two of getting salinity down. Trouble is, don't leave it too late or else your fish may have been too exposed through punctures in its skin to bacteria and infection etc...
There are as many views on treating (or not) WS as there are on what additives you should use for your tank. Back a horse and go with it, the worse thing we can do is change horses all the time and not know what works, or doesn't.