how to remove top of cab? (spot welds), 62 SWB

[fslay]

OK, this is kinda long, but I really need some help saving a '62 C10. I've really been working hard on my '62 short step by scraping oil and grease, priming and painting and such. The hardest part of the truck is going to be the cab. Near the top of the windshield, the cab has rusted through in several locations, but is currently saveable. It looks like the top panel itself (part over your head) should be spot-welded to the rest of the cab, presumably where the drip rails go around the top of cab. I have a spare top that I cut off another truck. If there was some way I could remove the top panel itself, I could easily get the plasma cutter in and repair the rot. I have no intention of severing the pillars completely and replacing the whole top for fear of not ever getting them back aligned properly. Does anyone know the locations of the factory spot-welds around the top of the cab for these trucks? Thanks in advance.