[dsraven]

just fab it up, less time and works the same anyway. maybe find a square nut at a farm store and it will fill the hole better. or
-measure off another door so you get the hole in the right place and mark an X on the door that extends out bigger than the hole but so the center of the X is the center of the spot where the nut should be.
-find a non plated washer that's bigger than the torn out spot that needs repair if the center of the washer were to be placed on the center of the X you marked.
-scribe a line around that washer. use a sharp pointed scribe so you get a fine line
-weld a non plated nut on the back side of the washer that is the same thread as what the door hole is supposed to be. using a lubed bolt inside the nut will keep any slag from messing up the threads inside the nut, just ensure you remove the nut before the weld cools off. set it aside to cool
-file or grind or burr out the metal from the inside of the circle you had drawn on the door, where the hole was. the washer should fit the hole and the center of the nut that you just welded to the washer should be in the center of the X you marked previously. a little space around the washer is ok, like the thickness of your mig wire (assuming you are mig welding)
-using a piece of scrap longer than the washer is wide, drill a hole in the scrap so you can bolt it to the washer that has the nut welded on. the scrap should be a little bigger than the washer, like some flat stock, so you can use this as something to hold the washer into the hole you filed out. it will keep the washer flat with the door. you can hold the scrap to the door with a screw, a small tack weld or a magnet or something like that. it is just thee to hold the washer in place and flat with the door panel till you get the washer tacked in a couple of spots
-once the washer is tacked in you can remove the scrap piece and finish welding the washer in.
-finish the metal nicely
-BOOM, done. and it looks like it was supposed to be there.
generally, a round hole is easier to fit a patch to than a non round hole. same for filling other holes, like firewall or dash. better to drill the holes bigger and use a nice clean round patch that you can buy cheap than waste time trying to get a patch fabbed up to fit the torn out spot or a bunch of different sized holes. some places sell the "unholes" (welders series, google it) so that makes it easy. use a step drill instead of a twist drill to get the right size so the hole stays round as you drill