Exciting Bruce! What do you plan to do to expedite the burn in process of the Alexx? I bet you're just dying to get to work with them. Their height looks perfect for your mastering suite.
According to Wilson Audio manuals you should do it with chamber music - it has high average energy and will speed burn-in. Probably also because it can be played loud without disturbing neighbors excessively ... My favorite favorite burn-in music is a recording of Bach Brandenburg concertos 4-6.