Ok picking up the landman smoky mountain at Costco. My bday comming up this month and was looking to add more smoke with a smoke generator from amazn web site. Help me pick the right one! Is it the tube? What size? Or should I get the box one? What kind of pellets should I buy? Pretty good size smoker with 4 racks. I'm new and it will be a gift for me so what's the best choice.