You do not have to soak beet pulp at all. Here
is a good article on beet pulp.
If you are the soaking type, pellets do take longer than shreds. But no where near 24 hours.
When I have forgotten to soak ahead of time I put hot water in them and while I am cleaning two stalls and getting hay together they have soaked up quite nicely.
Normally I simply put water in the meal before and they soak the 12 hours until the next meal.