Amen to the not judging by appearances!, 'nuff said. I tend to dress more formally than the general run of the public at these gatherings, but in hot weather I prefer a gillie or jacobite shirt, off white or in a colour complementary to one in my kilt. For informal evening, a shirt, (tie or not, as you choose,) and a waistcoat (vest), with the back made of the same material as the front, or if satin, fitted with no belt. I also modified a "western" jacket to have epaulets, much like the "Ike" jackets of WWII (we referred to this type of jacket as a "bum-freezer" to go with shirt & tie, or a turtleneck. I personally feel as long as the overall effect is pleasing to my (and my bride's) taste, that is all that matters.