This is my first batch of ribs this summer, and the first time doing more than 2 slabs at a time. I'm wondering how much should I increase the wait time for 4 slabs to be done.
The cook times for 4 slabs should be about the same 2.
The only time I ever noticed an increase in cook times is when I put a lot of cold meat on at once (several butts) and that's just because the cooker takes a while to get to temp with such a large cold mass in it. With just ribs you shouldn't notice any big differance.
Just out of curiosity Craig, how are you putting the ribs in the smoker? With four racks or less I'll cook them on a single grate in a rib-rack. Meatier ribs go on the outer portions of the rack and thinner portions towards the inside. Much easier than shuffling the upper and lower racks around.
Normally, Icook them on a rib rack, but I can't seem to find the one that I have. So I guess I'll have to lay them flat 2 on each rack. I'm not too big of a fan of rolling ribs. So I'll just lay them flat.