Body panel replacement tips/advice needed

that plan sounds pretty good. i would do a couple things different tho. i ve done it that way also, but you might wanna completely tack weld the entire outer seam. it will take time, but it will be well worth it. if you just plug weld the holes, you run the risk of that unwelded seam cracking. it will be a lot stronger if you just take your time cooling it and tack welding the entire seam. when i did mine..i completely welded the entire seam, front and back. took some time, but worked out good.
another thing you might wanna consider is..leading over the seam on the outside when you re done. duraglass is hard stuff, but it can shrink. i did this on a car once. i welded the whole seam, and ground it down. it was pretty flat, but you could still kinda see the welds. i blasted the seam to get it clean and then ground it up and coated it with duraglass. a little bit of filler after that, and smoothed the area out. it was straight and smooth. after a couple of years in the cold, and the seam started to show up. it didn t bubble, or crack, but you could kinda see the seam. it shrunk. you probably wouldn t even notice it if you didn t know it was there, but i could see it.
i know this sounds like a lot of work, but i d never take that chance again. i know a lot of guys probably get away with it, but....
in the first pic you can see the left vertical seam is finish welded and the top horizontal seam is half way welded.
the second pic is of the rear patch with the lead over it and filed and ground down.(sorry, i didn t have a close up of the other patch with the lead in it).