Hey folks! I'm scheduled to fly into Grand Cayman, landing at 12:30 after being in the air for about 6 hours. I've been invited to do a night dive starting around 6:30 that night. I'd hate to pass up on a night dive (this may be my only opportunity to do so down there) but I'm concerned that I won't have enough time between my flight and my dive to be safe. What is the rule of thumb here?