I've had good luck at school with the Amaco Potter's Choice and Coyote glazes. As you know they have to be thickly coated. (The kid who made the biggest mess actually made one of the best bowls we donated to the Empty Bowls project.) Try layering those Coyote Shinos over the black for some interesting effects. These cones 6 oxidation glazes make me in less of a hurry to built a gas-fired kiln.