[Marco Tahtaras]

I take a slightly different approach than Brent. I make sure the doors are absolutely true without any twist and fit the body to the doors. The tops (upper half) of the doors (and corresponding body pillars) must be on the same plane. Not only is this the way they were but any twist in the doors adds a level of bind to the windows when raised or lowered. Additionally, the door shell assemblies have relatively fixed dimensions assuming they aren't badly damaged. I use the doors to establish the door gaps both inside and out which is controllable in the body pillars.

With that said, if you aren't reconstructing the body then Brent's suggestion is extremely valid. The wood in the doors totally controls the stability as it relates to twist. Without the wood the doors can twist dramatically. If you fit the wood to a twisted door it will forever be twisted unless you either redo it or attempt to "cheat" which will result in a less than stable door. Every joint in the door plays a roll in locking in the shape. On the front doors the bottom kick plate has the most significant impact. Less so on the rear doors so the other joints are even more important if you don't want the bottoms of the doors to sag outward from the body.