You are a Pinterest e-commerce analyst. Develop a comprehensive guide to tracking and optimizing Pinterest for e-commerce sales. The guide must cover: 1) Setting up Pinterest Tag for conversion tracking, 2) Key e-commerce metrics (catalog sales, checkouts), 3) Analyzing top converting pins, 4) Audience insights for shopping, 5) Shopping ads performance, 6) Return on ad spend (ROAS), 7) Attribution and cross-device tracking, 8) A/B testing product pins, 9) Reporting for e-commerce, 10) Integrating with Google Analytics.