I have a #1, and I cut a full packer brisket in half. A full packer is going to be around 15-20 pounds. You will trim a coupe pounds of fat (hopefully not more than that!). It smokes beautifully on a #1. Just did another this last weekend. Put the point half – fat side down – on a lower rack (the point takes more direct heat and shields the flat), an the flat – fat side up – on a rack above it. Target temps are 195 in the flat, and 200-205 in the point. With this arrangement in the #1, you will find that each piece reaches it's target temp at around the same time. I've got this down to a science. It is foolproof if you buy quality meat, such as the PRIME whole packer briskets at Costco, which I bought this last week for $2.99 per pound. Okay, now for the size smoker you should buy. A full packer 15 pounds or less will probably fit in a #2 whole if you let it touch the front and back when you put it in (allowing for shrinkage). But is still a tight fit. I happen to think the two rack method is superior anyway, due to the different cooking temperatures and rendering requirements of the two different muscle groups. But...when it comes to buying decisions, I never once wanted a #2. My advice is always, if you are at all in question about which size smoker you should get, then you should get the larger one. In your case, if you are considering a #2, then that's probably what you should get.