I've brazed the wing to scuttle gap up before for someone who wanted a smooth joint between the two. It's took a couple rods each side but did a lovely job of smoothing the seam. The big plus of brazing rather than welding was that if the wing ever needed replacing you could just melt the braze out of the joint.
One down side is the heat, although you can control it to avoid distorting anything it will take off paint within 2-3 inches. I found a paint gun with a long nozzle and a bit or wax oil inside the scuttle void was required after wards.
The other downside of brazing is that it can crack over time.