Selecting values for UD table Keys

I need a second opinion before I implement a solution.
We are working on an integration with our customer facing website. I had programmed the integration with calling webhook endpoint via BPM data directives to trigger events on the website. This works great, but it doesn’t have a good way to process retries in the event of a failure.

Instead, I am going to modify the BPMs to write out entries to a UD table and then we are going to have a cron running on the website to call out to a BAQ service to get the needed data to trigger the website events.This will allow us to prevent retry issues.

What I’m hung up on is designing the the key fields in the UD05 table appropriately so that I don’t cause myself issues in the future.

The info I am capturing and writing to the table will be something like an ID, a timestamp, the endpoint needed to call, the json data to be posted, and then a spot for the cron to write back a success stamp + comment.
What would be a good schema structure to utilize?
Thanks