I have done a few prime ribs in my day but, I was asked to smoke the prime rib for my wife's work Christmas party this weekend. They ordered 30lbs of rib roast. I don't know exactly how big the roasts will come, but I am assuming they will be around 7-8 lbs. They are eating around 6 pm and I was wondering when I need to get them started. I understand I can pull them a little early and wrap in foil and towels for a couple hours and they will raise to the desired temp. My main question is how much time would you think it would take smoke four 8lb rib roasts at 235 degrees or so?