I'm about to commission a 4x1 peak-lapel DB dinner jacket from Steed. This will be based on a terrific 4x1 DB sport coat that they've previously made for me (see picture below).
The question is what type of waist covering to get. A common opinion is that waist covering is not necessary for DB dinner jackets. However, the 4x1 button layout presents some unique challenges. When one sits down in a 4x1, the lapels bow out at the bottom. This effect is charming in its own way, but it also makes it not unlikely for my waistline to be exposed to guests who happen to be standing up. Therefore, I think it's better to have some form of waist covering.
It's been suggested to me that I wear a cummerbund, but I prefer much prefer a waistcoat.
So, would a V-opening, low-cut, SB waistcoat be acceptable accompaniment to a 4x1 DB dinner jacket? This waistcoat will be completely hidden by the lapel lines of the jacket when I'm standing. Thanks!