I got some work done to the door panels also. Here's some pics of the work.
1) the plywood is shaped to the part of the door it gonna cover.
2) the holes are marked for drilling.
3) Drilled through the wood and the door skin for aligning the holes between
the two pieces.
4) Pilot hole in door.
5) then opened up the holes in the panel.
6) I used these little guys where you can't get a wrench to tighten nuts from
inside the door.
7) Here it is with the inserts in the right places and ready for the next step.