You don't need to set up similar channels from scratch. For example, once your "Google Shopping NZ" channel works, you can copy it to make "Google Shopping AU", or copy it into another client's shop. The tools are on the channel's Settings tab under Tools.
Duplicate channel makes a new channel with the same mapping, include and exclude rules, merge variants, categories and format options.
You can also use Duplicate in a channel's menu on the Channels tab, which copies it into the same shop.
When you copy into another shop, check the mapping afterwards. Rules that use fields the other shop doesn't have, e.g. a metafield or a global store field, give empty values until you add those fields.
Export settings downloads the channel's setup as a file. The file holds the mapping, include and exclude rules, merge variants, categories and format options. It doesn't hold server details or passwords.
Use it to keep a backup before a big change, or to send a setup to a colleague.
Import settings reads an exported file into an existing channel.
Feedsmith rebuilds the feed a few seconds after the import.
Under Danger zone, click Delete channel and type the channel's name to confirm. The feed URL stops working at once.