that's fine.. just take a small scrap of sheetmetal and bend it into an angle in a vice and put it behind... just try make sure things are tight, probably gonna need a couple screws to hold that one tight, not much clamp capability.... and plan where your going to weld before hand.. if the small patch has some larger areas, plug weld em...
everything should be fitted, screwed, marked for plugs, disassemble, drill holes, quick fit, grind EVERYTHING, weld prime the 2 inners of the sandwich, dry, screw together, weld, grind, prime, seamseal, paint, wheel with dry sneakers...