You might run into the problem of your screener answers not properly sending people to the Congratulations page. This is usually caused because no Ethnio token parameter is attached to the URL. Having 'advanced options' on your invite page activated will bypass the logic, so if you want to have logic enabled, don't active those advanced options.
I can't find any description of the advanced settings - specifically, the impact and uses of entering a 'custom url'.
Entering a custom URL will allow you to send recruits directly to the specified URL without having the go through the screener questions. For those of you who have not seen this option, click on "Show advanced options for this page" on step 2) Invite when creating and/or editing your screener. This is what you'll see: