Welcome to the forum! I think you will find it's slightly bigger but not by much. (Maybe a little taller?) I do like the adjustable bottom shelf. Here are some photos I took of the inside with a tape measure. Let me know if there is anything else I can do to help show you the size.
Yes you can move the bottom shelf flat (close to the heat source) or move it up about 2" (better for smoking). This option is perfect for grilling, especially considering the Ironwood can get up to 500 degrees.