OK, a few specific questions:

1) Must the waistcoat be white, as MacMillian states, or may it be black, as the Wikipedia article says?

2) Is the fly plaid permitted?

3) I don't foresee being able to afford any argyle, tartan, or diced hose anytime soon. Will black hose work?

Also, in case in makes a difference, the performers will not be seen together by the audience. We will go onto the stage one at a time, perform, take our bows, and then exit the stage. Once the recital is over, the audience leaves, and we meet friends and family outside the auditorium.