I am looking at getting a pair of Canadian combat pants for a friend (who measures are 40/31/41 weighing at about 150 pounds, stands about 5'10") and I found a pair that says a size small regualer and fits between 27" to 31" waist. The question is how tight fighting will they be? I am taking it that the old bdus where also NATO sizes so that why I am asking here. Can anyone help? Also what size of combat shirt should I be getting with it? Also if there are any pieces that go over the old canadian combat uniform like snow camaflug pieces or just a parka, do I go by the sizes like I would for the pants and dhirt or do I have to go up a size or two?