Jim, I've done four at a time a few times now, and like to start at about the same time as that(10:00pm) to have for supper the next day, with my Maverick (at vent) set to wake me up if temp gets out of the 215-265 zone. This keeps me within 200-250 at the grate.
Anyway, doing five for the first time in about a week. You cooked five before? I've got forty pounds of pork butt in the fridge and I'm wondering if all that meat is enough of a heat sink to skip the water. If it was winter, I probably would skip the water. I use Stubbs briquettes. What's your "three tier" system? I've heard of using skewers to stand three on end on a rack, but I'm probably gonna be leaning three against a beer can chicken rack. I'll put the largest two on the bottom rack.