Thank you for your post.
Your suggestion is fine. The only caveat that I can envision is if the PDF filename already exists for a previous record. By replacing the name, you would change the contents of the previous record. Therefore, make sure you export the contents of the Container field using a unique filename (possibly including Record ID).
I already saw this coming - what I had done is create a Folder for each user based on their account name.
Would you be able to share that script? What you describe sounds like a solution I could use. Does it work in IWP too?