Traeger is very misleading when they talk about the size of their grills.
For example ... The Pro 575 is advertised as having 575 sq inch of cooking space. However, its main grilling surface is only 22 X 19" (or 418 Sq. Inches). That is a SMALL amount of space when you want to smoke ribs. The 575 sq inch number includes the small 154 Sq. Inch second shelf.
Even the larger Pro 780 model is only 30 X 19" (570 Sq. Inches).. the 210 sq inch 2nd shelf makes it 780.
The Rec Tec RT-700, on the other hand, has a 36" x 19.5" grilling surface (or 702 sq inches). With its 2nd shelf, the total cooking area is 1054 sq. in. (but it's not called the RT-1054... its the RT-700).