Putting the follow-up list on the Home screen, with the 3-day no-answer rule, is the part I'd copy. One thing to check on the Viewed status: if the quote page records a view whenever the link is requested, WhatsApp may fetch the link to build its preview when the owner pastes it, and the owner opening their own link counts too. Quotes can then show Viewed before the client has seen them. Recording the view from a small script that runs in the browser after the page loads (a google.script.run call), and giving the owner a separate preview link that doesn't log anything, keeps the status honest. Since the follow-up list relies on that status, a false Viewed can hide the quotes that most need chasing.