Today I skinned one door! This is the thrilling tale of how I did it.
Started by sticking a bolt through this hole where the handle goes because that obviously these holes are supposed to line up.
Then swivelled the other side to where I thought it should be and put a cleco through it. This stopped the skin moving around while I bent the lip over.
Then I tapped the lip over all around about 1/3 of the way with a panel hammer, and finished it off with mole grips and a block of wood. No photos of this because I must have been concentrating too hard on the work.
A little bit of weld in each of the bottom corners, and the tops where the skin meets the window frame. Then back on the car it looked like this.
The door opens and closes OK which is good but the gaps are currently quite ugly. Behold:
I have fitted the hinges, latch and slam thingy in the b-pillar so that I can see how the final result will work/look and go from there. Still quite a bit of bending/adjusting/fitting/refitting x 100 to try to improve the fit, but at least the skin went on without getting destroyed. :)