Thanks for the replies, everyone! You all have me cracking up....

Thank goodness I'm connecting to a TATL flight in J with fully lie-flat seats! (No way I'd have paid for Business for this flight alone.) Maybe I should try to stay up on this flight to avoid back pain and then just sleep in the lay-flat later? Would be tough to stay up on a 4.5 hour flight departing at 3am, so I sincerely hope the aircraft has IFE. Jeez louise.

On another note, I booked through UA and am not able to select my seat for this flight online. If I call into Lufthansa with the record locator would they let me select a seat free of charge?

Thanks everyone!