Quick spot weld question

I would not weld the seams. Unless your an experienced welder (and I still wouldn't do it). You can create an edge that can stress fracture and crack, create pin holes and burn through for moisture to get in to. Spot welds are designed and used for a purpose and serve the industry well. Imagine the mess you are creating if you ever need to replace a panel. The over lap is destroyed. A good quality spot weld actually can create more surface area of the joint than the length of a weld. Staggered spot welds create strength across the span of the joint instead of linear along the edge. My wife (the mathematician), while I was explaining my answer to her. Stated a circle is stronger than a square or an edge.