Looks like a good plan. As mentioned by henry999, your seats would be in F in the U.S. (nothing to write home about, but still better than being in Y) provided there is availability. And don't give up from day one on those seats; have your TA check on a daily basis. That's what I did through the LH office here in Beirut (I recently completed a RTW in C too). Also, please make sure you save your boarding passes as I am sure some of your flights will not post to your account. Good luck and enjoy your trip.