You will find that many of the men wear dinner jackets or as you say Tux on formal nights and an equal number wear suits as a rule. The percentages will change slightly you can never be precise. I tend to wear a jacket and tie to dinner every night but I am the exception on casual nights and about 50% wear a jacket and/or tie on informal nights. Seldom are suits seen on the less formal nights. I am referring to the main dining room. All I can assure you is that you will not be looked at in a bad light if you are well dressed but often are if you are badly dressed. ... Neil.