I'm sure I speak for many people here when I say we are ready to stress test and the like. I spent a few moments reading and all I see is to use the matchmaking system which I will do so as instructed. I think it would be a good idea to get a thread up that tells us what you want the masses to test out and attempt to find fault with.
They do tell us through the updates. For instance, right now they want us to test the servers in our region. From this post: "- You have the ability to choose your default region now in settings (Currently just Europe and America, more coming soon), and quick match by region! Please make use of this!"