Bill, have used the powder in rubs and used the water and powder sauce on grilled chicken. It was hot and good.
Try it in a rub and let us know what you think.
Colman's is made from white and brown mustard seeds that are ground and sifted (through silk!) to remove the husks then blended together. Oriental mustard is ground and sifted brown seeds. It is thus a bit hotter but has a bit less range than the blend.