I added the 22.5 just before Christmas and used it for the first time on Monday. (Regardless of how big it looks, four 8 lb chickens will not fit on one grate.
The door on mine seems to have a big gap as well. I fiddled with trying for a better bend but need to work more on it. I did put a bead of high temperature silicone on the top and bottom joint so it does seal well enough to put out the remaining coals when the vents are closed.
You still need a mini to complete your collection (unless you already have one.
Perfect size to handle that fourth chicken.