int hours, minutes;
string proxy = project.Variables["ip"].Value; //Only the IP address should be in the ip variable (without protocol, port, login and password)
ZennoPoster.IpTools.GetTimezone(proxy, out hours, out minutes); // Get the proxy timezone by the built-in method ZP
instance.TimezoneWorkMode = ZennoLab.InterfacesLibrary.Enums.Browser.TimezoneMode.Emulate; // Включаем эмуляцию
instance.SetTimezone(hours,0); // Set the timezone