for brisket and butts I use the hour and 1/2 rule as a guide but that can vary for a number of reasons which I will not go into at this time. Ribs for spares which is what I cook I shoot for 4 to 5 hours, again this can vary and I use the bend test. For chicken if its whole I will go by the wing and leg wiggle test but from 45 minutes to 1 and 1/2 hours will usually get her done again depends on conditions. So determine your weights of the brisket and butts, put the heaver ones on first, usually the brisket and follow up with the butts, these two will take the longest. When you think the brisket and butts are about 4 to 5 hours out from being done ad the ribs and in a couple hours the chicken if you want it all to come of at about the same time. Now remember it will not hurt a thing to get the briskets and butts done sooner and have them holding in a cooler while the ribs and chicken are cooking. Just calls for some planning ahead, thats what competition cooks do every weekend for the most part.
When the going gets tough, I take more fiber.