For the last 30+ years I've always cooked with the hood up. Recently, with the purchase of my Genny, I've been cooking/smoking with the hood down. Even with the simple hamburger, I'd sear both sides (hood up) the cook it with indirect heat (hood down) for the remainder until done. Received many more compliments even from my family, who are totally familiar the my traditional hamburgers.
Murray, all I can say is experiment. With any new grill there's a learning curve to see what best works for you.
Enjoy the process,
elliot