Is shorts, t shirt and "nice" sandals (like Rockports) ok for dinner at Couples Negril?

I know that the one fancy reservation restaurant requires closed toe shoe, long pants and collared shirt, so I'm bringing for that. At the other restaurants I was hoping super casual is ok? I really don't want to dress up anymore than I have to, and I really don't want to have to bring resort casual (khakis, collared polos, etc) unless nessecary. Weight is always a concern when flying and packing for 10 days means I'd prefer to pack more shorts and Tshirts than having to make room for dress coded dinner/evening clothes.

All that aside I dress business casual to work every day. I'd prefer to leave that stuff at home if I can. But I don't want to look out of place either!