We use garbage bins to make our beet pulp at the barn. One usually feeds about 20 horses so I doubt you'll be needing that much!! :P We Put about 6 scoops (the metal scoops that people usually use for hay cubes) in and then fill them with water. It probably ends up being about a 3 to 1 water to beet pulp ratio. We use cold water so it does have to soak for a few hours. At a friend's barn they use tap hot water and again about a 3 to 1 ratio and the beet pulp mixes up in less than half an hour - you do have to feed it quickly though as making it with hot water will cause it to go bad faster.
Although you don't have to soak it, it is also good for getting some extra water into the horses, although it is not a substitute for giving free choice water.
They say money doesn't buy happiness -- well happiness doesn't buy horses!