EVZ is technically for eur/usd - but all fx is interconnected its a big web… so i use it on other fx pairs are there are currently not any other iv indices available on the cboe for IV volatility indice currency pairs - (obviously advise testing on other currency pairs if using EVZ as a filter on them)
not sure what you mean on times - i use this mostly during the day - but it does work ok at night as well
