Replicating Paid Ad Micro-Testing for Zero-Budget Indie Films Organically

For a truly zero-budget indie film, you can replicate the data-driven approach of micro-testing paid ads organically by treating different content variations across platforms as your 'ad sets' and closely analyzing native platform analytics for engagement metrics. Early on, when I was cutting my teeth on a documentary about urban farming (shot primarily on my FX3 with an ancient set of Rokinon cine primes and lit with a single LS 300x) I couldn't afford a dime for ads. Instead, I created 5-7 different short-form assets (6-10s hooks, 15s arcs, 30s mini-trailers) following the BlockReelDAO's 'scalable asset library' principle. These would range from a gritty, handheld visual-only cut with an intense soundscape, to a talking-head snippet from an interview, to a fast-paced montage. I'd post these variations across Instagram Reels, TikTok, and YouTube Shorts over a couple of weeks, consistently using the same few target hashtags but varying the captions to appeal to different 'motivation-based' angles. By meticulously tracking which posts garnered the most views, shares, saves, and comments within each platform's native analytics (which are surprisingly robust for free), I could effectively see which creative resonated most with my target audience, all without spending a cent. This allowed me to prioritize which content styles and messaging worked best for the longer-form film promotion, mirroring the iteration process of paid ad testing. The BlockReelDAO guide emphasizes 'participation design' and 'motivation-based targeting' which are incredibly relevant here: https://blockreeldao.com/blog/building-your-films-audience-social-media-marketing-for-filmmakers. What organic metrics have others found most indicative of audience interest and potential virality for their micro-tests?