I have no useable advice, only a similar problem. My door was torqued the same way. My neighbor who is an experienced bodyman told me that we would cut the whole section out at the flange where it mounts, get it straight, and weld it back in.
I have found that finding a single patch panel that goes top to bottom is not available as a repop, so its a donor cab required.
On mine, since the roof is pretty well collapsed, the drivers cowl is destroyed, and there are enough miscellaneous dents and dings, that I would go ahead and just replace the cab with another that is in better shape. Then use this cab to practice my bodywork skills. Or else beat on with a hammer when frustrations get the better of me.
I tried the "fill er with bondo" trick on another truck. result was not satisfactory. IF you have to, use the fiberglass filler w/ the strands. Then fill the waves with bondo.
My $0.02
