Fin width cannot change, at least not in the 5 FinFET technologies I have had access to. You have to understand that process engineers spent years optimizing the process for that specific width, this is not something a designer is going to play with. If, and this is a wild scenario, the fin width were to change, there would be consequences for device performance, leakage, pin/contacts, effective gate area, and so on. It would be a completely new technology, or almost.