Testing with CBO can be tricky. If You want to make sure your adsets all have a chance - Set minimum spend - Schedule a few hours ahead so They all get active at the same time - Make sure You know some KPIs or At least an estimate. Let the CBO spend for a days or so and look at your Numbers, pause anything That is bad (above your KPIs) and let the others run, if They improve more You can start looking at scaling them into a new Campaign. CBOs can be rly good for Scaling, But tricky for testing.