For me, the best system is to put the ribs last on the serving line and make sure you have a server to put one on the plate then ask if they would like another one. The big eaters will ask for more and the little eaters will pass or only want one. Meats are always last in line with chicken first, we use a three compartment plate so after you put bread, salad, beans, potato salad there isn't much room for a lot of meat the first time through and with three meats people usually only take one or two meats as it is. Most people in my area will take chicken so I always have enough chicken for everyone to have one piece and cut down on the other meats.