If you want to learn the best way to use Microsoft infrastructure products then you should look at how microsoft has been employing them. Microsoft proudly boast that they "eat their own dogfood". What that means is they are using pre-release builds of products in production ont heir own networks. This enables them to test, tweak and learn the best ways to implement the solutions.
Microsoft makes a lot of this information available, in particular, their Exchange infrastructure. They have shown how 55,000 global users with a lot of email activity are served by 3 or 4 data centres with clustered Exchange. They’ve just released a document that explains their current processs for configuring their SMTP gateways to maximise performance, usability and security.