I take a different approach. I only use as much of the patch metal as I have to, as others have stated. Then I work the patch metal to have the same contours as the body, next hold the patch in place and mark the outer edge. Cut the body about 1/2" shy of the mark. At this point using clecos I attach the panel along the very edge. Using a end post grinder and a cut off wheel I start cutting through both the patch and the truck removing clecos and tacking as I go. You must be carefull to get the metal in the same plane as you advance. I stay about three inches behind the cut. After all the cutting and tacking is complete I skip around mig welding the seam and the cleco holes until it's all one piece. Grind the welds and more times than not, the resulting fit up requires no filler
