Offline Conversions with Custom User IDs

[Jonathan Kressaty]

I have a number of offline conversion events that happen at various times after an ad click (simple things, from records created in other services to interactions with the customer). We use a custom User ID to identify individuals based on an internal service, and that is available on our site at all times, so we send that to our gtag implementation for use in remarketing later.

The conversion tracking guide for offline events mentions that the gclid is needed to attach a conversion event to an ads click. I technically have the gclid, but there may be multiple clicks in a given time period, and I'm not sure of the future attribution needs we may have.

Since we have custom User IDs being synced to the ads account, is there a recommended/available path to tracking offline conversions with a User ID instead of the gclid?

Thanks for any and all thoughts!