One other trick i've used successfully is to not actually go-live on the actual launch date. But go-live much before that and have restricted signup or somethin

One other trick i've used successfully is to not actually go-live on the actual launch date. But go-live much before that and have restricted signup or something. This way you can signup and test around your site in its full production config(even run payments) You can configure the webserver to show a different landing page if a particular key/cookie doesn't exist. To avoid unauthorized access to the public sections not yet publicly launched