I made this one for my LJ top. I don't have room in the garage so it just sits outside next to my shed. The upright ones look a bit "tippy" to me. I'm sure they're fine if you have good floor to roll them around on but as mine stays outside I opted to store it flat. My dimensions won't help for a TJ but to be honest, I just grabbed some lumber & screws and went at it.
View attachment 13067