Personalizing Emails Based on Lead Time Zones: A Guide

How can we personalize emails as per Lead’s time zone ? I have been trying to get UTC timezone based on company HQ location or contact location and wrote an extremely long GSheet/table if/then function that assigns UTC timezone based on top 1,000 cities in the world, i.e. “San Francisco” = “UTC-7” Get {{utcDiff}} “San Francisco” = “-7” and adjusted the logic in the Instantly JS by adding/subtracting {{utcDiff}} from the time_h server UTC.