Update: Removed the passenger side cowl with the vents that my friend Bill cut up vertically trying to establish an acceptable door gap. Test fitted a replacement cowl with no vent. The replacement still left no gap. So I created a pattern of the shape of the front of the door (just because, see first picture). I used that pattern to slice the replacement cowl from top to bottom (see second picture). Now I can position the piece of the cowl that establishes a gap, as necessary (see third picture), and then trim a little bit off of the front piece of the sliced cowl so that I can weld them back together and... have an acceptable gap.
Now the hard part... can the old man weld the two pieces of the cowl together such that it will cosmetically be acceptabe? I have a better chance of accomplishing that since I will be welding it "off the cab".
BTW... got a heliocoil kit to fix that one, stripped 3/8-24 bolt.