Pick seat 4A for the person who loves window view.
Row 5 becomes row 6 across the aisle.
You will get it when you get on board.
If you are happy to sit in J on either the 330 or (sad if its swapped) 737, then good.
Best of luck.
Thanks for the tips , after looking at the seat map i think best seat for us will be 4A 5A and 6E .