I’ve spent the last 2 days finding dozens of ways how not to do this… so I would really appreciate some help!
I have a custom state list of emails and a custom state list of subjects (“talents”). I want to create a single record for each email, for each subject:
Where 5 emails would have the same 5 subjects associated with them, I need to create 25 records - where it inserts a record with each email and each subject, once.
I have been using custom state lists, backend workflows and iterations of the custom state lists which (:minus) items from my lists - but nothing I have tried is working so far. I either get a bad loop (thousands of records being created) or I get duplicates appearing and I just can’t seem to get it right. My logic is to:
Hopefully this is enough information for someone to advise on the best practice approach here - I am all ears! 
Thanks,
Adam