X2 on Weedeater's suggestion for slides, especially if your going with upper and lower grates. Reaching to the back of a 24" smoker trying to get some meat out, all the while avoiding the upper grate would be a pain. Make life simpler, slides. The only time my upper grate comes out is when I'm doing turkeys or beer can chickens, because they are too tall. I spaced mine out 5 1/2" between the 2 grates, this gives plenty of room for even the largest of briskets, butts and even whole shoulders. Your door appears to be larger and cut higher than mine, so you might be able to spread them out a bit more.