We group all of our copy tasks within our project, and we have an approval for each one. The design task associated is a dependency on approved copy. The teams use a google sheet for all of the copy (Emails in one tab, Social in another, Ads in another). For content (such as articles) we list those under content. All of the groups work off the same creative brief. It has served us well to a point, however where the copy and design work equally as hard we have run into issues where we feel they need to be produced in direct collaboration to prevent copy that doesn't quite work for the designers being all the way done and approved, and turning into rework.