Aww they are super cute. How exciting for you, congratulations on your new baby, and welcome to EBN. I look forward to seeing more of you and your new baby, and to seeing lots of pictures of Mr. Cuteness.
We use the 24" X 36" for our females and for Buddy we have a 28" X 42" Buy a wire crate for him as they provide better ventilation. It will come with a divider so you can make it smaller at first, this will help with potty training. Then as he grows you can move it back and eventually take it out. I would also buy the two door version.
I myself use the X Large crate. I want them to have plenty of room when they get older. They also have a crate that has a divider in the middle, so you can use half of the crate when they are young. You don't want them to have too much room in the crate, or they might potty at one end of the crate. If you don't have the divider you could use a piece of board.