The trays on mine are 4.5 wide and 17" long. I remember when I bought mine Bob has trays that are adjustable in length up to 22" maybe. Have to look and see. I bought the wireless motor for comps and it states will turn 25-30# of meat. IMO that is high. I loaded all 4 trays with spares and sounds like it works a little hard. I am going to buy an electric motor for when we have power at comps and use wireless as back up.
I can say I love my rib-o-lator though. Done chicken, ribs and salmon on it. You should have no issues doing a brisket as long as it is cut to fit trays.
18.5 & 22.5 WSM-Weber one touch. Cyber Q Wi-Fi. Head cook Thick and Thin BBQ