Interesting, So I would get say 4 lengths or threaded stock, say like this maybe a few inches longer, I was thinking of going 20 inches.
Everbilt 5/8 in.-11 x 24 in. Stainless-Steel Threaded Rod-00969 - The Home Depot
Then I would say weld or bolt on a bracket on the bottom section, and one of the top section in each corner, like a heavy gauge steel l bracket, drill two holes shove in the rod, put on the nuts and then work it up a little on each corner.
What kind of weight are we dealing with, do you think, would maybe I use small pieces of channel steel for the brackets, and maybe grind them off when I am finished?
When you put in the new pieces, did you weld, or did you rivet. Those rivets look heavy duty and pressed on by some high force, so did you just weld the new supports in place?
Also, the plan was to just weld new sheet metal over all those windows and go with new custom frames or double pane glass, cause I would freeze to death when I am in Canada. Is that what most people do?