When making vertical glaze tests for crystalline glaze: throw a simple cylinder with the catcher attached. When throwing, make the tall cylinder first; pulling enough clay to the top in order to form the catcher. So on the wheel, this image would be inverted with the catcher on the top of the cylinder. You can make the tall and narrow, or short and wide to fit the kiln you use. As you progress, and get your glaze recipe dialed in: little glaze will run off.