Congrats.....and since you seem to be burdened with two, I would be more than happy to allow you to "store" one here with me....just for safety purposes and so you won't be wasting so much space at your place.
Dang and props! I'm killing myself over the 70-200mm F2.8 Z. This would be the better lens for my stable, but $$$. 420mm@F4..., 600mm@F5.6... Congrats!