How to use external Tor node?

I would like my Whonix Gateway to use a external Tor node found elsewhere in localnetwork. To accomplish in standard Tor Browser outside Whonix I can edit the settings “network.proxy.socks” and “extensions.torlauncher.control_host” with “extensions.torlauncher.start_tor” as false. How can I do the same in my Whonix Gateway?

+1000 internets if you can also say how do it in Whonix-Qubes