At Thistle, our Meta ads are split into two audiences: Retargeting: This audience comprises recent Thistle website visitors who have started but not completed sign-up. Starting sign-up includes providing an email address. Prospecting: This audience includes all other Meta traffic (albeit with some limited targeting, such as living within a Thistle delivery area). We currently spend the majority of our Meta budget on prospecting, although our retargeting cost per acquisition (CPA) is generally lower (as measured in-platform). How would you determine the appropriate spend split between prospecting and retargeting campaigns?✱