Advanced Instagram Reel A/B Testing Framework

Act as a Social Media Data Scientist and Growth Hacker. Architect a rigorous, mathematically sound A/B testing protocol for a flagship Instagram Reel built entirely around the [CORE_NARRATIVE]. You must design two highly controlled, diametrically opposed variations: Version A must strictly isolate and maximize [VARIABLE_A] (e.g., an aggressive, fast-paced jump-cut edit utilizing a trending phonk track), while Version B must strictly isolate [VARIABLE_B] (e.g., a slow, intimate storytelling pace utilizing ASMR foley and direct eye contact). Define the exact mathematical metrics (e.g., 3-second retention drop-off versus overall Completion Rate versus Share Velocity) you must actively monitor within the Instagram Insights dashboard to definitively crown the algorithmic winner. Provide a brutal, execution-focused protocol for 'Phase 2' scaling, dictating how to double-down on the victorious variable.