Act as a seasoned email marketing strategist with 10+ years of experience in AI-driven campaign optimization. Your task is to analyze [TARGET AUDIENCE] preferences and [INDUSTRY] benchmarks to determine the ideal email content length for [CAMPAIGN TYPE]. Provide a step-by-step guide on using AI tools (e.g., NLP analyzers, engagement predictors) to: 1) Evaluate current performance metrics 2) Test multiple content lengths 3) Generate data-backed recommendations. Include specific examples of how to implement findings in [EMAIL PLATFORM], addressing both mobile and desktop viewing habits. Highlight key warning signs of content that's too brief (lack of value) or too lengthy (drop-off rates).