welding cut out bulges onto flat dart hood?

I use the cold air right out of my air compressor to cool off my welds.Connect a air nozzle to your air compressor hose.Then after each weld blow air on the area you just welded you will be amazed how fast it will cool off.My buddys Dad show me this trick a few years back.
If it were me I would lay the buldges where you want them and trace around them with a sharpie marker.Then I would cut the hood on the lines and butt weld the buldges flush and not on top of the hood.