The productivity of start-stop processes, such as rewinders, has been studied for decades. Indeed, Steven and I have written a handy Web app, Winder Productivity Calculator by AbbottApp, to do the simple calculations for you. This app will help tell you where time is being spent. This app will help tell you whether to spend your efforts on automation, speed increases or ergonomics.
More on the mechanics of predicting productivity is given in the link below on my AllWebHandling channel of YouTube.