Rick,
No bracing. As long as you have a solid floor pan or sill they provide all the bracng you need. The only thing that's going to move in this situation is the distance between the bottoms on the striker and hinge pillars.
Think of the door opening as a ring of steel. Unless you are in a collision or other destructive event that circle will never change, BUT if you cut a piece out of the circle you can visualize how that gap could open and close. In the case of these trucks, the sill and floor pan are the primary supports for this dimensional stability. Remove one and you're okay. Remove both and you're in trouble unless you brace. I learned this many years ago when we cut the roof off a
PINTO and that is something that has never changed... and why convertibles have such heavy frames.
In my case I did one at a time and my door fits and latches perfectly... indicating that my door opening is what it should be.
