You can get those separated with a $20 spot weld cutter bought off Amazon. I have cut a whole car apart with the 10 tips they give you. The trick is to keep the cutter centered on the spot weld, the cutter tends to walk around. I do this by center punching the spot weld with a sharp pointed punch for the collapse-able pin in the center of the spot weld cutter to ride in. Drill slow till the cutter is seated and lubricate with paraffin. Any old candle will do. Just poke the hot cutter tip into the candle. Use moderate drill speed till you get the hang of how it cuts, it is easy to drill through both panels so care must be taken until you become proficient. I would cut out some of the welds on areas of the panels you plan on not using. I use an old skinny small flat blade screw driver to separate panels and a flat blade pry bar to hold it open as I go. The small screw driver doesn’t bend when striking it with a hammer and the small tip not only gets into tight areas better, it cuts through easier cause of the small tip.