Using Allan's advice on formal wear for the cheap, I bought an Eton jacket from the uniform comany. I have a night time "Black tie optional" dinner to go to on Saturday and have the dress shirt and black tie to go with my Modern MacDonald tank with matching flashes. I'll have to try to do the buttons in the hotel room between now and then. Looking at all of the pictures of people in formal wear I am unsure if I should be wearing a belt with decorative buckle or not? I also have a white rabbit fur sporran with a small decorative at the top. Would this affect the use of the belt or not?

Any help appreciated.