Help !!! 72 Roof replacement recommendations

[Pablo85]

I have a 72 c10, my roof is very rusted so I ended up buying a roof from a 67donor cab, the new roof is in great shape, nothing compared to mine.

I would like to have some recommendations from where to cut my rusted roof, I'm planning to cut it from the A pillars and to cut at the back at the rear seam, the rear seam has like a lip and it is spot welded, so I'm going to take the outer roof from both of the cabs, and I will take the opportunity to clean the new roof's surface rust, paint it with some rust preventer and put some dynamat on it.

As I said, my plan is to cut the roof from the a pillars on the top of the windshield frame like I drew on the picture, I'm going to make a kind of sheet metal guides in order to cut precisely both pillars. At the rear I'm going to take out the outer roof so that way I'm going to have just the inner roof and the A pillars, then I'm going to drill all the spots welds from the back of the inner roof.

I'm also going to put some inner structure to hold the old roof, so when the old roof goes off and my A pillars are cut, I will put the new roof on the structure and everything should fit perfectly, since it will hold it, it would only be a matter of welding everything back.

My real question is: Do you think it's a good way to do it? I have seen some roof replacement on this group, but I think it's better idea to cut the roof from the rear seam and put everything back.

I will put some pictures of my truck and some blueprints of the parts of the cab that I found on other groups.