I think there's always enough sent in exhaled human breath to allow deer to pin point you no matter what clothes you wear. It's hard not to exhale while in the bush. So go with the down wind approach and high tree stand method.
Maple
Scent -Hunting Clothes - Underwear and out and up from there
As for control of breath, you could chew on a balsam or spruce tig or nettles, even if the taste is not good. Mother Nature's breath freshener.
Old Indian saying, if a leaf falls from a tree in the woods the turkey will see it, the deer will hear it, the bear will smell it, the moose will not eat it, but be on the look-out for LeGrand.
