Generally the way to sort out this sort of thing is to start with the inner structure (floors and sills under the cabin), then work outwards to the outlying structure and panelwork. Always do one bit at a time (1 sill or one corner) and don't start on the next until that's finished. Not clear from your photos what the structure is like. Worth a good look underneath with a screwdriver to suss out what every bit of structure is like. My dad used to have a 250V8. Sold a few years ago as he only ever used it to get to the MOT station. I borrowed it only once and ran over the dog . Lovely car to pilot though.