MacMillan, as is usually the case, especially on dress and heraldry, is both accurate and to the point. While I am not one to choose ink for myself, I'm not completely opposed. To anyone contemplating what you are, I would say contact your clan chief. If he is willing to provide you with a graphic of what he would approve, on his letterhead, then proceed as you wish. If not, I would find another path to honor my forebears. As MoR pointed out, the Lyon Court does not reach here, but your clan chief's authority over his property rights and his clan rights does not have boundaries.