In my experience, it's wise to do whatever the bride asks. If she says she "prefers" the black kilt, then wear the black kilt. If she says she prefers ruche ties, then wear a ruche tie (even if it pains you to do so). If she says she likes the pleats in front, then wear the kilt backwards.

In the end, it's her day, and I would consider myself lucky if my brother and future sister in law were considerate enough to think of my clothing preferences when planning a wedding.