I think formal and semiformal nights are on the sea days, and pirate night is on Tues, if that helps you narrow it down. I'm thinking menus are posted somewhere for the 7 night (anyone know?) If you book the romance package or are in a cat 1-3, your booking opening is 105 days out so you can book now. If you are castaway member, reservations open up March 15th provided you have paid your cruise in full. If DH were going, I would try to score a Palo reservation but since he's not, I am passing. The brunch is the harder ressie to get as it as well as high tea is only offered on sea days.
Our first time we cruised, we had no reservations for Palo, didn't even know we could book them the first day (we were clueless - did not even know that DIS boards existed

) , so we told our waiter at dinner that first night that we really wanted to go and he was able to get us ressies (we were on a 7 night eastern - can't remember which night). We also had no excursions booked and just winged it.
(I think we rented a car in St Marteen, and booked one excursion in the other port right on the ship.)
Does anyone know what time you can start booking on the 15th of March? Is it 12:01am eastern? I guess its like the cruise - lots of people book as soon as they can making multiple ressies, then cancel when they narrow down their plans. So if you don't get them at first, try, try again!