I sometimes do if there is something important to get back for. Since the ride will end mid to late afternoon, I wouldn't make a reservation earlier than 5pm or so. That should give you enough time to get to the ferry in time for the reservation. If you are early, then you have enough time to either stop for apres or a quick bite at a cafe.
When you arrive at the Equestrian center don't un load your bikes till you know what your groups plan is. The groups will be leaving from different spots.
Thanks