I know speciality booking times on Azamara are offered at 6/6:30 and 8/8:30 however we have never had a problem with arriving earlier than our booking time. We like to eat somewhere between 7:15 and 7:45. We book the 8 or 8:30 time, then turn up at about 7:45. We’ve nearly always been seated immediately and no-one has ever told us we are too early!