Have to agree with M.L.
It's all up to the indivdual and what they feel comfortable in. This is a VACATION not a fashion show after all!! Dress up nice in a Dark Suit and feel comfortable. I saw people without any suit coats on at all in the dining room. And the STRIPE down the side of the pant leg is a REAL THING OF THE PAST!! Most of your really expensive Tux's don't have those anymore unless you're really looking for that style. Remember it's WHAT you FEEL COMFORTABLE IN!! Now don't forget to have fun on your cruise!!