For Motiva Message Testing AI components with an end date, we suggest the following rule of thumb:
Provide enough contacts to send each message variation at least 150 times per day.
For example, if your campaign will run for 5 days, and there are 8 message variations, then your population should have at least 6,000 contacts.
5 days * 8 variations * 150 contacts/variation/day = 6,000 contacts
Generally, the more data Motiva has to work with, the better it will help your campaigns perform.