On formal nights (2 on our cruise) men wore dinner jackets or suits, ladies were dressed to match but not over glamorous. Other nights casual or informal, some men had suits others jackets jumpers some wore ties others didn't. All the ladies had obviously changed but none were "over the top"
Some people avoided the formal meals by going to the bistro but most people appeared to have changed from day wear to something more dressy in the evening.
If you go to the top of the main questions page, you will find a search engine. If you find Transocean Tours in the Cruise lines, and Marco Polo in the ships list, then click on "search", probably ALL of the questions that you want to be answered will appear before your eyes! Good luck and happy cruising.