Running a new sponge in an cycled tank will "seed" the new sponge right away. There is no more or less to seeding the filter media. I would say to let it run an hour more as a system check i.e.. flow, fit, leveling, vibration etc.
Once seeded the bacteria will establish based on their food source...PERIOD.
HOWEVER, a seeded filter is not an established filter, don't push the envelope to hard. We get in trouble with ammonia spikes, because the bio-filter is over loaded.