I have a landing page I'm A/B testing in Google Optimize, trying to see which variant of the landing page yields the most email signups. The problem is, I can count how many signups through the site I get using a Google Tag Manager and then linking that with the Analytics, but I want to see how many emails are signed up through which landing page. The emails are being counted through a trigger using the Mailchimp embed form id.
To make things more complicated, we're using a survey as the thank-you confirmation page, off of a different domain. Tried using the thank you method, but even if that could work, I am guessing it would yield the same results of just capturing the total number of email signups, not necessarily where each one came from.
So, so far I'm using Mailchimp, Google Tag Manager, Optimize, and Analytics.