Returning a bit to the topic ...

Can someone tell me which seat (window, middle, aisle) is best in terms of under seat space on:

777-200

and

737-900

My wife will be bringing a puppy from Belgium back to CA in eight weeks. In cabin reservation has been made. We have done this trip with a puppy twice before on UA (no one even knew the puppy was there as it slept the entire trip), but it's been three years since the last puppy and I know the cabins and seats seem to be always changing. In particular, which seat(s) have the electronic boxes taking up space. FYI, it will be a soft sided carrier, so can always make due, but better to pick a seat without "extra" boxes under the seat.

Thanks in advance.