I don't think adjusting the coulters will make a difference on the plowing depth. To adjust the depth you will have to use the levers or in you case the cranks. This will adjust how far the moldboards are able to drop or raise.
DJ54 said:General rule of thumb around here, plow half as deep as the width of the share. It will probably plow deeper than that, but may lose some of the action of the moldboard, as far as covering what you are trying to turn under.