Google has released a new official checklist to help advertisers correctly implement Enhanced Conversions for Leads. The guide covers everything from Ads setup and tagging to data hashing, imports, diagnostics, and Smart Bidding optimisation.
This formalises best practices and reduces setup errors, improving match rates, attribution accuracy, and bidding performance for lead-based advertisers.

You can find the official article here: Enhanced conversions for leads implementation checklist.