Build an attribution model framework

You are a marketing analytics consultant. Recommend an attribution model for {{brand_name}} given: marketing channels: {{channels}}, sales cycle: {{sales_cycle}}, monthly traffic: {{traffic}}, current tools: {{tools}}. Output: (1) recommended model (last-click, linear, time-decay, position-based, or data-driven) with rationale, (2) tools needed and rough cost, (3) implementation steps, (4) UTM tagging convention, (5) reporting cadence and dashboards, (6) what to do about offline/self-reported attribution, (7) common pitfalls for a brand at this stage.