If you are going to remove the automatic tip (which obviously is your right) any tips you give to your steward or wait staff will have to go in a "pool" they are not allowed to keep it. Only if you keep the automatic tip on do they get to keep it. Seems a bit unfair but that is how it works. When we sailed on the Sea Princess I dressed up on non formal nights husband wore shirt and tie and smart trousers, no jacket, the British seem to dress up more on these nights,just dress as if you were going out for a meal or night out at home
Just returned from a cruise on the Sea Princess, Brill Ship and we have 3 children so removed the automatic tips and tipped who we wanted at the end of holiday, takes 2 minutes to do at pursers desk and is no problem.
Less formal nights hardly see anyone with a jacket or suit, mainly trousers and open necked shirts.
You will have a great time, we did!
I think you will find that the formal nights in the Med are a bit more formal than caribbean....we went last year and most people wore suits, shirt and tie, on formal evenings. But agree it was a lovely ship!