I am a big fan of applewood for ribs, and I use the 2-2-1 method but if you prefer more bite and less FOB, then do 2 then 1 1/2 then 1. I also do the foil wrap with squeeze butter crisscrossed then honey crisscrossed in the opposite direction and sprinkled with dark brown sugar, then flip them - meat side down in a throw away sauce pan and covered tightly with foil (makes it easy and less messy when un-foiling). save the juice in the pan when done, makes a great dipping sauce. Put back bone side down for the last hour and use Sweet Baby Rays. But I don't think six racks are gonna even come close to feeding 50 people, maybe the first 10 or so folks are gonna be happy, the rest of them are gonna be mad...lol