Those are going to be a stout set...
I have a set of Dave's Off Road doors on my '81. I was kind of skeptical of the fence latch they used but no problems yet..

Though I would like to come up with something using a stock latch from a set of donor doors I have.
Hard to tell but
http://4xinnovations.com/pages/guarding/doors.htm have a longer latch.
Sounds like you are on the right track for figuring out something to keep stuff in....Cel phones slide out very easy

I know