I have a #2 and can smoke more than enough for most occasions. My kids got me the rib rack for the #2 for father's day...it has 7 slots and holds 3.5 racks of ribs, cut in half. I also throw a couple of baked potatoes in the top rack. That's more than enough ribs for my wife and kids, so I usually do 2 racks and foodsaver left overs.
I can fit two 6# chickens side by side in the smoker, and I will occasionally do an 8# butt on one rack with no issues. A 13# turkey fits nicely, and I have done a couple of 6# turkey breasts side by side on one rack. When I do the mac & cheese smoke, I can fit a 12x9" pan on a shelf. Other than that, it holds more than enough chicken breasts or thighs for pulled chicken, etc.