The idea being the non tapered will scrape the water off more efficiently. Maybe in a controlled environment you might notice a difference. I would be more aware of using heavy metal/ceramic shoes. They do have gripping power but have better metal than the drums. When a wheel cylinder sticks or park cable holds they eat up the drums. So just be aware if brakes indicate any dragging , repair quickly..
Got me thinking perhaps metal spray might restore drums too? And what if they could be hardened?