Useable grill surface is anything under 10″ W X 13″ D X 5″ H and must be positioned carefully over the grease plate to avoid the grease fire. So again, any hunk of meat less than your grease tray and not touching the lid should be ok if positioned with care.
https://www.amazon.com/Traeger-Grills-Ranger-TBT18KLD-Pellet/dp/B07CT4FPG6

