I would recommend that you learn and understand how collection proxies work and how you load and unload them. It seems as though you are well underway and I believe the answers in the thread will help you understand them fully.
It can be a hassle to manage the loading and unloading of collections/screens and if you have many different proxies that you load and unload I’d recommend that you spend the time to write your own screen manager to take care of this. If you design it well it can be reused between your projects. You could also take a look at the routing library that was posted a while back. It’s well written and will take care of all your screen management problems.