Best way to separate pinch welds

The replacement, cut off bedsides are ~30 miles out, it'll be a minute before I'm ready to retrieve them/ but they are complete cutoffs from an 8', 80s D150. They cut thru the front wall and all the way down the length of the bed, "just" inboard of the wheel wells. Other then drilling from the "inside" of the bed towards the outer wall, I know no other way to seperate the upper lip (where the stake pockets are) from the inner fenderwells and be able to use them, than to drill out every spot weld.....
Mine probably aren't "bad enough" to replace complete bedsides/ could get away with patch panels over the wheel wells.... but the PO was one who would scrape the sides of an airplane hanger pulling in/backing out..... and I have what I have here, which are the replacement full bedsides rustfree from Georgia already.... and Ive done the "patch panel" thing before and been disappointed. looked GREAT for ~2 years then it started rusting exactly at my seam.... so if I do complete bedsides, I won't have to worry about that.