Definitely avoid 10 across configurations. After that, I'd look at the seat maps and see which flight had the best availability for preferred seats. For example, if you are 3 people, then where could I get three seats together that are not next to the lav or galley. After that, I'd go for the emptiest flight, hoping for an empty seat next to me etc.--though knowing that much can change til flight time.

I wouldn't worry about food, etc.--it will keep you going (think frozen dinner quality) but will not be good no matter what.