I don't plan to quote anyone here. But I believe that some may be allowing bias show. It fine to have preferences, everyone does. But to claim a personal preference is the tradition, can mean you don't see a bias.

OC Richard has kept this board filled with board filled with wonderful photos, and illustrated photos of the past. There is also the fact that we live in a world with an internet. A record of wing collar shirt worn with and for black tie is not hard to find, both in photo/picture/illustration and text. And has existed long enough to not be dismissed as not traditional.

I will admit my bias, I think a well made wing collar shirt can look fine with black tie. But not traditional? That's not really true. Only the hire shop? Also not true. The 'I've never seen it', 'It's not done', 'Not in my circles', it all boils down to preferences. We all have them, and travel in different places that show them. This is a 'no true Scotsman' fallacy literally. Anyone is free to disagree, and I can respect your individual choice, but this is a preference issue, certainty not one to be codified as tradition vs. non-tradition.

So to the OP; there is no 'code' for the shirt. If you want a wing collar style, and do not plan to get one with a detachable collar, get one with a very high attached collar. There are a great many resources for formal wear, both black, and white tie, where shirt types are broken down.

Best of luck at your event. I have been to many formal Regimental events, and a kilted turnout always goes well.

UBIQUE

Frank