From our experiences in J and F with travelling with an infant. Choose the seats at the back of the cabin and closest to a galley. This has a number of advantages.

1. People are less likely to book there (everyone wants to be close to the front) so more likely of having a spare seat to spread out with.

2. Pax who do book near you once they see an infant will usually move forward (if you know it is empty you can make the helpful suggestion ).

3. Having the galley nearby allows you easy access to the bathrooms for changing and also you can duck back in their if he becomes restless - which is appreciated by the pax and crew.

That is what works for us...remember what were once great seats for you, may not be good for an infant.

Mark