A crew of 5 is great. And I believe in what sailingdog suggested of staggering watch crew-motion is a good thing-especially at night. It's also a great way to get to know the other crew. And two on for night is always good.
Clipping on is a must at night and anytime someone is topside solo, even during the day. My last delivery we had a crew of 4-one seasoned sailor was sick as a dog the first 36 hours and unable to keep his watch. Made it tough for the rest of us. A thermos of hot water is always good-pre-packaged meals in case the weather is bad-lots of protein snacks to grab-chocolate is a must-and we've always had a no booze until we arrive policy. Red light headlamps are a good thing. Make sure you have back up
binoculars-charged
VHF for ditch bag, also a must.