Little window to big window

[aboz]

I came across a 1960 big back window cab in a parts yard the other day and was wondering if anyone out there knows the proper way to graft it in to my small window '63. The doner cab itself is shot so it would be impossible to just switch the cabs out. Should I leave the glass in and cut out as much of the surrounding metal as I can? Will leaving the glass in while welding the graft to my cab prevent warpage? If anyone has ever tackled this chore please advise. Thanks Aboz.