I'm following you now... The JD design has separate bolts for the pivot of the impact force and another to lock the ROPS upright , but your pin is designed to do both. Your intent for the hinges is to just hold the ROPS when you have it folded down, right?
Your fab skills seem good and you probably already thought of it, but you may want to ease all of the edges that will be pointing straight up when you have it folded down.
Good luck with the install and remember this is one of those projects that we don't want see pictures of you testing it out after it's installed!