We did a Mini Truck years ago........ It's kinda one of those things ya just gotta do as you go along
We boxed the windsheld frame and across the back of the cab. so we could seal it. We cut the door window frames off the doors and welded them into the top so when the top was removed there was no frames on the doors The frames also had to be cut so as to allow the door to open with the top on and the windows up I can't get the link to open to see the latches you were talking about and I can't remember what we used latches off of the guy that owned the truck got them at the junkyard but not sure from what I think something like a MG

MM64