I just helped a buddie do his before I moved from florida.
The new lower skins, slide up from the bottom of the door and are lipped
on the sides and bottom. So it wraps around the door, then you just spot
weld around the sides and bottom and you can glue or weld along the top
then put filler in on the seam. I'll cut out the bad spots first then put
welders primmer on that and go from there.
My friends came out real nice and you could not even tell it had been done
after just the filler was added.
Kurt