First I think that cutting an AD cab to put those panels in is a horrible, expensive idea. For an expert rod shop sure, for the average hobbyist good luck. There is a much easier and less expensive way to make the conversion. First start with a set of these from a donor cab.
https://www.flickr.com/photos/advance-design_parts_co/8129371322/in/album-72157631868452754/Next without major surgery and having to endure door fitment and gutter issues not to mention difficulties around the belt line, you cut the outside like this.
https://www.flickr.com/photos/advance-design_parts_co/18849826063/in/album-72157631868452754/Look at the relative size and heat affected areas, which are small and localized.
https://www.flickr.com/photos/advance-design_parts_co/19282884008/in/album-72157631868452754/The inside is simply a replacement of the existing panel, you weld where opportune (read small) and the joint between the two is at the pinch weld.
https://www.flickr.com/photos/advance-design_parts_co/18849820823/in/album-72157631868452754/https://www.flickr.com/photos/advance-design_parts_co/19444386216/in/album-72157631868452754/https://www.flickr.com/photos/advance-design_parts_co/19284317059/in/album-72157631868452754/You can work one side at a time, all variables are controllable. I have sold 8 sets of these to people from parts trucks (no I have no sets for sale). One person I helped had it paint ready in three days, another person who gave me an email back was near the same time.
Again with less than a professional set of skills and tools that method is not the easy way to do this conversion, nor is it inexpensive. I used to sell the pictured set on eBay for $250-300 which included the glass as shown. You will be into the panels, glass and shipping well over $1000 on the other set.
