Not sure about the A340, but on the A330 row 4 would be your best bet. Take 2 middle and a window. Really, your only options are row 4 or 6 since they are the only seats with a bassinet (LX will make you sit there, IME)
@KidOOO, it really depends your value on miles, money etc, but if your other option is coach for 42.5 I would pay the extra 37.5k to have business for the main leg.