Okay, so the woman on your arm at a formal dinner isn't exactly an 'accessory' but couldn't decide where else to post this question.

My kit is all put together for our first formal St. Andrew's dinner but my wife is wondering what is appropriate to wear besides the tartan sash. Of course, I'll be in prince charlie, bow tie, kilt, hose and ghillies.

Please forgive my ignorance, relating this from memory but...

Floor length evening gown? Cocktail length? Evening black or White or off white? Whatever color best sets off the tartan sash? Any other comments?

Thanks in advance.