We recently had a vintage herringbone cotton knit that needed buttonholes on the henley placket. The knit was fairly loose and, though buttonholes wouldn’t have been impossible, they would have distorted over the life of the shirt.
Enter: cording. If you find rat-tail cord or some other trim (they made it in this case) you can easily make corded button loops and offset the buttons slightly from the center without redrafting the front. It is whipstitched or couch stitched in place on the inside of the placket.