Remember bolting mild steel shelves to stainless steel will create galvanic corrosion. The mild steel is anodic to the stainless. So the mild steel will rust even with seasoning. Stainless to stainless will last longer and not have rust in your food.
I was in the same boat and chose Stampede because I also have a 6 burner Weber Summit, so did not think I needed the extra 6”. Since, I made the right decision because I can still cook 3 butts or 4 racks of ribs with plenty of room.