Sizing is slim. I wear 31 in APC New Standards or Petit Standards and pretty much 32 in everything else. I have several pairs of 32s from Ovadia & Sons. Although I could squeeze into them, I ultimately had an inch let out of the waist. Next time I order pants from them, I will get 34s (and I don't own a 34 anything). So I would say strongly consider a 30, especially if you are planning on tucking shirts into the pants.