Robbie, A Class 5 hitch pin is rated to 30,000 lbs.... I thought the same way as you did,,, But then I thought about that and the heavy loads a hitch pulls,,,
I still don't trust the class 4 stuff... so I am using OD 2x2x.250 wall tube for the Male and the Female will also be .250 wall fully welded and also gusseted like crazy,,, then the pin will be 5/8 " and we will use 2 pins...
Now that seems like going overboard,, but I am like you and like STRONG, but I want removable too.
Charles