Ravage, my recommendation would be to go with the new panel. It is extremely difficult to copy any body lines and the exact shape of the panel if you patch and use bondo filler. You can keep the original tabs from the old panel and attach them to the new when fitting the metal. Another tip is to use a strip of metal behind the butt seam before welding. The metal should be about 2 -3" wide with the seam in the middle. Use aircraft Clecos (basically simulates as a spring pop rivet that can be reused over / over) to hold both sides together and in shape for mig welding. Clecos are available through
www.aircraftspruce.com. They are about $0.35 ea and the pliers are under $20. They are excellent for body work. I know because I built an all metal RV6 aircraft before embarking on my Chally resto.
Best of luck whatever you do
Barry